What i did wrong in this question is firstly i misread the first option A and secondly didn't focus on the main theme exposure of a type of food to a one-year-old for developing taste.
though i eliminated option C, D, and E
But also eliminated option A due to misreading of two year old to one year old.
Correct Explanation :
(A) states: “Two-year-olds do not naturally prefer salty food to sweet food.”
Why is this needed? Because if two-year-olds naturally shifted to liking salty more than sweet even without exposure, then the observed change in taste could simply be due to natural development, not exposure. That would undermine the conclusion that exposure caused the change.
So, the argument assumes that the change doesn’t naturally happen in two-year-olds (without salty food exposure) — exactly what (A) states.
However, I choose option B as the correct option
(B) says: “A child’s taste preference usually changes between age one and age two.”
This suggests that taste preference changes normally, regardless of exposure. But the argument claims that exposure to salty food causes the shift.
If (B) were true, it would actually weaken the conclusion (by implying taste changes anyway). Thus, it is not an assumption required by the argument.