A can give B 100 meters start and C 170 meters start in a kilometer race. How much start can B give C in a kilometer race?
Choose the correct choice from the following.
A) 11.77 meters  B) 55.77 meters  C) 77.77 meters  D) 113.77 meters  E) none of these

Rationale: "explanation : a runs 1000 meters while b runs 900 meters and c runs 830 meters . therefore , b runs 900 meters while c runs 830 meters . so , the number of meters that c runs when b runs 1000 meters = ( 1000 x 830 ) / 900 = 922.22 meters thus , b can give c ( 1000 - 922.22 ) = 77.77 meters start answer : c"
Answer: C