Read the following sentences. Only one is correct. Which one?
A. Spring begins March 20 but die-hard skiers can find the best conditions in North America into early July.
B. Spring begins on March 20 but diehard skiers can find the best conditions in North America into early July.
C. Spring begins on March 20, but die-hard skiers can find the best conditions in North America into early July.
D. Spring begins March 20, but diehard skiers can find the best conditions in North America into early July.