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 number of proper subsets of the set {α, β, Φ, θ, η} is

1. 24
2. 25
3. 31
4. 32

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

If A = {x : x ∈ N, 5 ≤ x < 10} and B = {1, 2, 3, 4, 5}, then n(A - B) is equal to

1. 1
2. 2
3. 4
4. 5