主题：【Help】A Math contest question -- steve

My nephew got stuck to a Math contest question. I would highly appreciate it if anyone could give a lift.

How many four-digit positive integers x are there with the property that x and 3x have only even digits? (One such number is x = 8002, since 3x = 24006 and each of x and 3x has only even digits.)

(A) 82 (B) 84 (C) 86 (D) 88 (E) 90

Thanks for all your help!