Possibilities are Student A has 2 and the others 1, Student B has 2 and the others 1, Student C has 2 and the others 1. So let's just find out how many possibilities lie in each of these three scenarios, and then multiply by three.
Student A may have any two books of four (order is irrelevant), giving six possibilities (1&2, 1&3, 1&4, 2&3, 2&4, 3&4). Of each of these six possibilities, there are only two ways to distribute the remaining two books to each student. So, there are twelve possibilities for each of the three listed scenarios.
12 x 3 = 36. C.
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