I haven't got any milk left. I must go to the supermarket and buy some.
A. I haven't got any milk left, for I must go to the supermarket and buy some.
B. I haven't got any milk left, or I must go to the supermarket and buy some.
C. I haven't got any milk left, but I must go to the supermarket and buy some.
D. I haven't got any milk left, so I must go to the supermarket and buy some.