If 7 boys meet at a reunion and each boy shakes hands exactly once with each of the others, then what is the total number of handshakes Select the correct option:
A) 21
B) 42
C) 43
D) 44
E) 45

Rationale: "n ( n - 1 ) / 2 = 7 * 6 / 2 = 21 answer : a"
Answer: A