George and Betty have a son, Charles, who is a sophomore in college. Their modified AGI is $160,000. Charles received Form 1098-T from the college that indicated he was at least a half-time student and that he paid tuition of $6,500. Charles didn't have a felony drug conviction at the end of 2018. What is the maximum amount of educational credit that George and Betty can claim on their return?

a) $1,300.

b) $2,500.

c) $4,000.

d) $1,000.