for what value of y would the following be true?

[(1/3)πk(3 + 1/4 y)^8/3] = 2[(1/3)πk(3^)8/3]

(weird symbols are pi)

A.)6.2
B.)6.1
C.) 2.0
D.) 3.6

The question seems odd because many factors cancel to give:

(3+y/4)=3*(2)^(3/8)
which when solved for y, I get 3.56.