Which of the following is a pair of disjoint sets?

1. A = {even natural numbers} and B = {prime numbers}
2. C = {multiples of 2} and D = {multiples of 3}
3. E = {factors of 24} and F = {factors of 9}
4. G = {letters in the word 'RHYTHM'} and H = {Vowels in English Alphabet}

The cardinal number of the set A, defined as A = Set of all prime numbers less than 100, is

1. -20
2. 22
3. 24
4. 25

The sets {a, b, c} and {x, y, z} are

1. overlapping sets
2. equal sets
3. singleton sets
4. equivalent sets

A = {x : x is a prime number} and B = {x : x is an even natural number}. Then A ∩ B is

1. an empty set
2. a singleton set
3. an infinite set
4. equal to A