Is this a, b, c, or d?

Answer:
Alright so let's start by elimination.
Step-by-step explanation:
It cannot be 1/4 (unless it's y or x)
Cannot be 1/2 unless it's the bottom part.
So that leaves you with 1/3 and 1/6, 1/6 is to small so it has to be 1/3.
Hope this helps!