An error 1% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is:
Choose one: A) 2.01 B) 30.1 C) 3.01 D) 25.01 E) 4.05

Rationale: "explanation : 100 cm is read as 101 cm . a 1 = ( 100 × 100 ) cm 2 = 10000 and a 2 = ( 101 × 101 ) cm 2 = 10609 ( a 2 - a 1 ) = 10201 - 10000 = 201 = > 201 / 10000 * 100 = 2.01 answer : a"
Answer: A