Hello everybody,

Could someone help me with this problem?

1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16

Two integers fom 1 to 16 are chosen at random and their corresponding square in the above grid is shaded. What is the probability that these two shaded squares form a rectangle?

a. 1/10
b. 1/8
c. 1/6
d. 1/5
e. 1/4

Answer is d


Thanks and good luck!

JJ