The correct answer is answer D: aquéllas
D is the correct answer because shirts, or camisetas are written in the feminine form! Here's the problems with the other answers:
A: It's written in the masculine form and is missing an accent mark
B: It is not plural! And the word camisetas is!
C: It is written in the masculine form.
So, the full sentence you are looking for is:
Estas camisetas son grandes, pero aquéllas son pequeñas.
Because it is written in the right form, it is plural, and it has an accent mark! Hope this helps you out!!!
