Your answer is the second option: The surface area of B is greater than the surface area of A.
To find the surface area, I found the area of the three sides shown and added them together, and then multiplied the answer by 2, so:
B:
8 × 2 = 16
8 × 10 = 80
10 × 2 = 20
+
= 116
116 × 2 = 232 cm²
A:
5 × 8 = 40
5 × 4 = 20
8 × 4 = 32
+
= 92
92 × 2 = 184 cm²
So therefore B > A because 232 > 184
I hope this helps!