Jeff volunteers his time by working at an animal shelter. Each year he works for a total of 240 hours. So far this year, he has worked 97 hours. Which equation will solve for how many more hours (h) Jeff will volunteer for?
A97=240+h
B97=240h
C240=97+h
D240=97-h
A97=240+h
B97=240h
C240=97+h
D240=97-h