In a board game, when you land on a specific square, you must roll a die. If the result is an odd number, you receive four times the result, in dollars. If the result is even, you must pay five times the result, in dollars.
Determine the expectation.

a. 5 - 4
b. 4 x ( 1 + 3 + 5) x 1/2 - 5 ( 2 + 4 + 6) x 1/2
c. 0
d. 5 x 1/2 - 4 x 1/2