The mean and variance of a random variable X having binomial distribution are 4 and 2 respectively, then P (X = 1) is

- 1/4
- 1/8
- 1/16
- 1/32

**Answer**

np = 4

npq = 2

q = 1/2, p = 1/2, n = 8

p(X = 1) = ^{8}C_{1} (1/2)(1/2)^{7}

**The correct option is D.**