Which of the following is the best correction of the run-on sentence below?

We ran to catch up with the bus we missed it by just a few seconds.

A. While we ran to catch up with the bus. We missed it by just a few
seconds.

B. We ran to catch up with the bus, we missed it by just a few
seconds.

C. We ran to catch up with the bus. But we missed it by just a few
seconds.

D. We ran to catch up with the bus, but we missed it by just a few
seconds.
SUBMIT​