**Question**

**Find Missing Number?**

A. 2

B. 1

C. 21

D. 20

**Answer:** A

**Solution:**

Now we have a pattern of prime numbers because 2 is the 1st prime number and all other numbers are prime numbers.

Therefore**2**, 3, 5 , 7 , 11 , 13 , 17, 19 . are in prime number series pattern.