The set of numbers which are the multiples of 5 is: (a) a finite set (b)an infinite set(c)a singleton set (d) none of these.

Dear student,

Let A be the set which are multiples of 5
A = { 5, 10, 15, 20, 25,....}
As we can see that the multiples of 5 can be infinitely many.
Hence the set is an infinite set.

Option (b)

Regards