Correct choice is (c) infinite
The best I can explain: Between 2 and 3, there are infinite numbers which are rational numbers like 11/5, 12/5, 13/6, 17/8 and so on. They all are integers and no denominator is zero so they are rational numbers. Thus, we can find infinite numbers who satisfies this condition.
So we can say that “There are infinite rational numbers between any two integers”.