My answer:
d)

first we can see that 17 +15 +15 = 47, and 22*2 = 44. 47 - 44 = 3. As 3>0 there is at least one student that took more than 2 composers.

a)

It's obvious that Hermione Granger would take 4 composer. However there only are 3 different composers chosen, so it's impossible to take more than 3. At least 3 students have taken 3 composer.

c)

As we just saw 3 students is a possible answer, but lets check the others.

e)

We are talking about students so some of them won't have the work done. if 5 students haven't done their homework, we have 17 "good students". Among them we could have 15 that chose 3 composer and 2 only 2 for a total of: 153+22=47 composer. OK that's possible.

b)

As we explained both c and e are possible answers. From here we can take 2 different paths: say only b is correct as we can't find the correct answer between c & e, or say that both c & e are correct (that's to say b is incorrect).

I would choose:

answer b.

My answer:
d)

first we can see that 17 +15 +15 = 47, and 22*2 = 44. 47 - 44 = 3. As 3>0 there is at least one student that took more than 2 composers.

a)

It's obvious that Hermione Granger would take 4 composer. However there only are 3 different composers chosen, so it's impossible to take more than 3. At least 3 students have taken 3 composer.

c)

As we just saw 3 students is a possible answer, but lets check the others.

e)

We are talking about students so some of them won't have the work done. if 5 students haven't done their homework, we have 17 "good students". Among them we could have 15 that chose 3 composer and 2 only 1 for a total of: 153+21=47 composer. OK that's possible.

b)

As we explained both c and e are possible answers. From here we can take 2 different paths: say only b is correct as we can't find the correct answer between c & e, or say that both c & e are correct (that's to say b is incorrect).

I would choose:

answer b.