#### Which of the following is a prime number?

(a) 69

(b) 87

(c) 91

(d) 97

**Solution:**

#### Which of the following is a pair of twin- prime number?

(a) 19, 21

(b) 43, 47

(c) 59, 61

(d) 73, 79

**Solution:**

#### The number of distinct prime factors of the largest 4-digit number is

(a) 2

(b) 3

(c) 5

(d) none of these

**Solution:**

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