If x, y, and z are selected independently and at random from the interval [0, 1], then the probability that x >= yz is

A) 3/4

B) 2/3

C) 1/2

D) 1/3

E) 1/4

The answer is A

I got it right, but couldn't figure out how to actually calculate it, I just guessed that it must be pretty high. Its obviously greater than 1/2, but my limited knowledge of probability theory prevented me from getting any further.

Thanks.