CONCEPT: The question uses the concepts of Probability .

SOLUTION:
 

The probability of the faces are proportional to the numbers on them,
=>Let the probabilities of faces bearing 1,2,6 be x,2x,......,6x respectively.

Since one of the faces must occur, we have
x+2x+3x+4x+5x+6x=1

x= 1/21
Thus, the probability of an even number =2x+4x+6x= 12x=12* (1/21) =4/7 (OPTION D)