If i sample with replacement, which of the following may be true? a. the numerator for the next event's probability changes. b. the denominator for the next event's probability changed. c. both the numerator and denominator for the next event's probability change. d. none of the values used in calculating the next event's probability change.

The numerator of the probability is how many ways there are for your
random draw to be successful.  That's how many of the marbles in the
bag are green, or how many of the socks in the drawer are black.  You
may be looking for one color with the first draw, but a different color with
the second draw.  So the numerator may change. 

The denominator of the probability is the total number of marbles
in the bag, or socks in the drawer.  If you replace each sample
before you try another draw, the total in the bag doesn't change,
so the denominator will be the same number for the next one.

The choice that summarizes this reasoning is ' A '.