Assume each variable has a different value. Which relations below are functions? a. {(a, b), (a, c), (a, d), (a, e)} b. {(a, b), (b, b), (c, b), (d, b)} c. {(a, b), (c, d), (e, f), (g, h)} d. {(a, a), (b, c), (c, c), (d, e)}
A. choice a only
B. choices b and c only
C. choice c only
D. choices b, c, d only