虽然浑身酸软，可是不干活不行呀！（ ?）

虽然浑身酸软，可是不干活不行呀！（ ?）
A、Though I still ached all over， I could not but to work.
B、Though I still ached all over， there was nothing to do but work.
C、Though I still ached all over， I must work.
D、Though I still ached all over， I had to work.
正确答案：D