Biology surface area to volume ration

Hi, please could i have help on this question? I thought the answer would be B because it has the highest surface area to volume ratio but the answer is A?
Here is the question: https://app.gemoo.com/share/image-annotation/634851688693051392?codeId=M078yEzWXaLng&origin=imageurlgenerator
Thank you!!

Coloruless quickly, large SA:V
A: SA 2(3 x 30) + 4(30 x 30) = 3780. V = 2700. SA:V = 1.4:1
B: SA 6(6 x 6) = 216 V = 216 SA:V 1:1
From inspection, D has a smaller SA:V compared with B. Same reason for C.
Check your calculation for A.