A fruit seller sells mangoes at the rate of Rs.9 per kg and thereby loses 20%. At what price per kg, he should have sold them to make a profit of 5%?  Choose the correct choice from the following answers:
A) rs . 11.81 B) rs . 12 C) rs . 12.25 D) rs . 12.31 E) none

Rationale: "solution 85 : 9 = 105 : x x = ( 9 × 105 / 80 ) = rs . 11.81 hence , s . p per kg = rs . 11.81 answer a"
Answer: A