What Must Be True If K_M Is Truly a Measure

What must be true if K_M is truly a measure of the affinity of enzyme and substrate?

A) k_cat must be larger than K_M
B) k_cat must be smaller than K_M
C) k_cat must be about equal to k₁
D) k_cat must be much smaller than k_-1
E) k_cat must be much larger than k_-1