Greg and Carl work at neighborhood car wash facilities and are paid daily. Greg is paid $25 a day plus $7 for each car he washes. Carl earns the same amount per car washed, but his total earnings in a day are always $6 more than Greg's. Which equation expresses the total amount, t, that Carl earns, as a function of the cars he washes, c?
A)t=19+7c
B)t=25+7c
C)t=31+7c
D)t=25+13c