The compound interest earned by Sunil on a certain amount at the end of two years at the rate of 4% p.a. was Rs.326.40. Find the total amount that Sunil got back at the end of two years in the form of principal plus interest earned.	Select
A) rs . 4326.40	B) rs . 4236.40	C) rs . 4136.40	D) rs . 4316.40	E) rs . 4136.40

Rationale: "let the sum be rs . p p { [ 1 + 4 / 100 ] 2 - 1 } = 326.40 p ( 4 / 100 ) ( 2 + 4 / 100 ) = 326.40 [ a 2 - b 2 = ( a - b ) ( a + b ) ] p = 326.40 / ( 0.04 ) ( 2.04 ) = 4000 amount = 4000 + 326.40 = 4326.40 answer : a"
Answer: A