A sum was put a simple interest at a certain rate for 5 years. Had it been put at 2% higher rate, it would have fetched Rs. 250 more. The sum is:  Choose the correct option:
A) s . 2000
B) s . 2500
C) s . 3000
D) s . 3500
E) s . 4000

Rationale: "explanation : let the sub be rs . x and the initial rate be r % . then x ã — ( r + 2 ) ã — 5 / 100 â ˆ ’ x ã — r ã — 5 / 100 = 250 â ‡ ’ x ã — 2 ã — 5 / 100 = 250 â ‡ ’ x ã — 5 / 100 = 125 â ‡ ’ 5 x = 12500 â ‡ ’ x = 2500 answer : option b"
Answer: B