We are only given figures for the percentage increases in consumption. The passage does not discuss anything about revenues, costs or profits. Can’t infer this one.

A deceptively attractive answer choice.

I have talked about this above as well. it is certainly possible that the immigrants consumed more poultry than fish, and that eating habit was the reason for a less than 6% increase in total fish consumption and a more than 6% increase in total poultry consumption.

Remember though, our objective here is to find an answer choice that must be true on the basis of the above passage.

So, can we be certain that for the immigrants, fish was less likely to be a major part of their diet than was poultry? No.

1. The passage doesn’t state that the population increase was solely due to immigration. Immigration was just partly responsible. May be bulk of the population increase was domestic.
2. Even if the population increase was solely because of immigration, we don’t know what caused the respective increases in fish and poultry consumption. It is possible that there was an overall trend in the country of shifting towards higher poultry and lower fish consumption.
   
   Note: Some test takers get attracted to this answer choice thinking that “This could justify why the consumption of fish and poultry increased the way they did. It fits.” Our objective is not to find something that could fit, though. It is to find an answer choice we can infer. We cannot infer (B).

Sure, 9 is twice 4.5. But those figures just represent the percentage increases in consumption.

We do not have any information about total consumption in absolute terms. e.g. fish consumption could have gone up from 1000 tonnes to 1045 tonnes (a 4.5% increase), and poultry consumption could have gone up from 200 tonnes to 218 tonnes (a 9% increase). So, poultry consumption need not even be greater than fish consumption in 1989, let alone be twice as much.

Were fish and poultry products a “regular part” of the diet?
No idea.
All we know is that their consumptions increased by 4.5% and 9%. What were the bases for those increases? We have no clue.

True story: I consume significantly more apple cider vinegar now than I did ten years ago.
Does that mean that ACV is a regular part of my diet?
I know for a fact that it is not 🙂

Consumption going up doesn’t mean that the food item is a regular part of the diet. Cannot infer this answer choice.

We know from the passage that fish consumption has increased. This option talks about a decrease related to fish consumption. These two pieces might seem contradictory to each other. They actually are not. The 4.5% increase in the passage deals with overall increase in fish consumption. This answer choice talks about a decrease in per capita fish consumption.

Let’s first understand what ‘per capita consumption of fish’ means.

Per capita consumption of fish = Total fish consumption by weight / Total population

The passage tells us that the numerator of the fraction has increased. This answer choice is talking about the overall fraction decreasing. Both these pieces of information could be true simultaneously. At least there is no contradiction here.

Now let’s see why we can infer it.

From 1980 to 1989, fish consumption increased by 4.5%, and the population increased by 6%. Fish consumption increased by a lower percentage than the population, therefore the per capita consumption of fish (the overall fraction) would have certainly reduced.

We can understand this algebraically too:

In 1980
Say, the total fish consumption was: F kg
Say, the total population of Jurania was: P

==> Per capita consumption of fish in 1980 =  F/P kg per person

In 1989
Fish consumption increased to: F*1.045 kg
Population increased to: P*1.06
==> Per capita consumption: F*1.045/P*1.06 kg per person
= (F/P) * (1.045/1.06)

1.045 < 1.06
==> 1.045/1.06 < 1
==> F/P * 1.045/1.06 < F/P

Thus, yes, the per capita consumption of fish was certainly lower in 1989 than in 1980.