Answer:
A)Pay off his personal loan for his entertainment system.
Explanation:
Late or delayed payments result in bad credit scores.
If Mark skips his car payment, this will make the matter more worse for him.
If Mark applies for as many cards as he can, this will further accumulate debts on him. Further purchase of cards does not help in getting good scores.
If Mark makes lower monthly payments on current bills, he will have to pay more interest and more amount after few months, when the amount will accumulate. This will take his scores lower.
So, the best possible option is option A. If he pays off his loan then his scores will improve.