Somebody please help me with this answer

I think it might be b. I'm super sorry if I'm wrong I tried my best :(
Answer:
Cube a
Step-by-step explanation:
You can compare them only if they have the same units of measure.
Ft -> m:
3.28ft -------- 1m
17ft ------------ x
x=17×1/3.28=5.183m.
Thus the cube a (5.183m) has a larger size than cube b (5m).
Hence the cube a has a larger surface area.