A dishonest dealer professes to sell goods at the cost price but uses a weight of 800 grams per kg, what is his percent? Choose the most appropriate option
A) 25 %  B) 25 %  C) 29 %  D) 55 %  E) 45 %

Rationale: "800 - - - 200 100 - - - ? = > 25 % answer : b"
Answer: B