v=360
formula
If a set contains ‘n’ elements, then the number of proper subsets of the set is 2^n - 1.
In this problem,
n = 4
2^4 - 1 = 16 - 1 = 15 proper subsets
y = –2x^2 + 36x + 6
x=15
y = -2*15^2 +36(15) +6
y= -2(225) +540+6
y=-450+540+6
y=96
Answer: Choice B