(i) Given: The set of months of a year.

As we know set is a collection of well defined objects.

Let we represent the given set in roaster form:

⇒ Set of months of a year is {January, February, march, April, May, June, July, August, September, October, November, December}.

Because the set contain 12 elements. Hence, it is a finite set.

(ii) Given: {1, 2, 3, . . .}.

As we know set is a collection of well defined objects.

As it is already represented in roaster form:

⇒ Set = {1, 2, 3, . . .}.

Because the set contain infinite number of natural numbers. Hence, it is an infinite set.

(iii) Given: {1, 2, 3, . . .99, 100}.

As we know set is a collection of well defined objects.

As it is already represented in roaster form:

⇒ Set = {1, 2, 3, . . .99, 100}.

Because the set contain finite number from 1 to 100.Hence, it is a finite set.

(iv) Given: The set of positive integers greater than 100.

As we know set is a collection of well defined objects.

Let we represent the set in roaster form:

⇒ Set of positive integers greater than 100 = {100,101,102,…}.

Because the set contain an infinite number from 100 to infinity. Hence, it is an infinite set.

(v) Given: The set of prime numbers less than 99.

As we know set is a collection of well defined objects.

Let we represent the set in roaster form:

⇒ The set of prime numbers less than 99 = {2, 3, . . .99}.

Because the set contain finite prime number from 2 to 99. Hence, it is a finite set.