In the first 20 overs of a cricket game, the run rate was only 4.2. What should be the rate in the remaining 30 overs to reach the target of 250 runs?  Choose the correct choice from the following options.
A) 6.25  B) 6.28  C) 6.11  D) 5.53  E) 6.21

Rationale: "required run rate = [ 250 - ( 4.2 * 20 ) ] / 30 = 166 / 30 = 5.53 answer : d"
Answer: D