The best efforts of the school's debate team were not enough it returned from competition with a second place trophy.

A.
The best efforts of the school's debate team were, not enough it returned from competition, with a second place trophy.
B.
The best efforts of the school's debate team were not enough, it returned from competition with a second place trophy.
C.
The best efforts of the school's debate team were not enough, and it returned from competition with a second place trophy.
D.
The best efforts of the school's debate team were not enough returning from competition with a second place trophy.