In two months, the legal minimum wage in the country of Kirlandia will increase from five Kirlandic dollars(KD5.00) Per hour to KD5.50 per hour. Opponents of this increase have argued that the resulting rise in wages will drive the inflation rate up. In fact its impact on wages will probably be negligible, since only a very small proportion of all Kirfandic workers are currently receiving less than KD5.50 per hour.

Q. Which of the following, if true, most seriously weakens the argument?

A. Most people in kirlandia who are currently earning the minimum wage have
been employed at their current jobs for less than a year.
B. Some firms in Kirlandia have paid workers considerably less than KD5.00
per hour, in violation of kirlandic employment regulations.
C. Many businesses hire trainees at or near the minimum wage but must
reward trained workers by keeping their paylevels above the pay level
of trainees.
D. The greatest growth in Kirlandia’s economy in recent years has been in
those sectors where workers earn wages that tend to be much higher
than the minimum wage.
E The current minimum wage is insufficient for a worker holding only one job to earn enough to support a family ,even when working full time at that job.

This is a re-constructed problem. They say the correct answer is (B), but I think it's (C). I'm not 100% sure about that, though. Can someone tell me what the correct answer is and give me some detailed explanation?

Thanks in advance.