The area of a triangle will be when a = 1m, b = 2m, c = 5m, a, b, c being lengths of respective sides?  Choose the correct option:
A) 3 B) 6 C) 4 D) 9 E) 1

Rationale: s = ( 1 + 2 + 5 ) / 2 = 4 answer : c
Answer: C