Critical Reasoning

Mrs. Su is an avid baker. She is especially proud of her light, fluffy angel food cake, which she always bakes before 8 a.m. She often says, ‘I have been baking my angel food cakes for over 45 years and I have never put one in the oven even one minute past eight in the morning! My cakes have come out perfect every time. Therefore, the key to a perfect cake is to make it before eight in the morning.’
What is the basic flaw in Mrs. Su's argument?

A. The time of day a cake is baked is important only at some altitudes.
B. She has never varied her method and therefore has no basis for determining which factor is responsible for the result.
C. She has never varied her method and therefore has no basis for claiming that her cakes are perfect the way they are.
D. It is well known that cakes baked in the afternoon are lighter and fluffier than cakes baked in the morning.
E. In fact, Mrs. Su never tastes her own cakes and has no basis for the claim that they are perfect.

OMO , its the choice B.
if she had baked a perfect cake everytime with different recipies and ingredients but still got a perfect cake then the assumption of doing the cake in the morning holds true.
since we dont know if she used the same method everytime, the choice is B.
OA pls?

OA : B

But why can't it be E ?

I feel that the choice E is scope shift. No one talks about who tastes the cake in the passage. No one defines what a good taste in a cake is.!

So I feel E is a better option