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))
((a, b), (c,d), (e ), (9, 1))
di a, a), (b, c), ( c), (d, e))
choices b and conly
choice a only
choice conly
choices b, c, d only