An error 4% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is:
Choices.
A) 4.16  B) 5.16  C) 7.16  D) 8.16  E) 9.16

Rationale: "explanation : 100 cm is read as 104 cm . a 1 = ( 100 × 100 ) cm 2 = 10000 and a 2 = ( 104 × 104 ) cm 2 = 10816 ( a 2 - a 1 ) = 10816 - 10000 = 816 = > 816 / 10000 * 100 = 8.16 answer : d"
Answer: D