A random variable X has the following probability distribution.

X : 1 2 3 4 5 6 7 8

p ( X ) : 0.15 0.23 0.12 0.10 0.20 0.08 0.07 0.05

For the events E = { X is a prime number } and F = { X < 4 }, the probabili y

P ( E F ) is

( a ) 0.87 ( b ) 0.77 ( c ) 0.35 ( d ) 0.50