Perform each of the following subtraction operation. Select the correct simplified form and its non-permissible value.
(3y/8) - ( 5/6y)

a. (3y-5)/2(4-3y) , y ≠ - 4/3
b. (9y²-20)/24y , no non-permissible values
c. (3y-5)/8-6y , y ≠ - 4/3
d. (9y²-20)/24y , y ≠ 0