It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.

1. A.
   which , that
2. B.
   that, where
3. C.
   whom, that
4. D.
   which, where

It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.

It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.

It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.

 It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.

A. which, that                                B. that, where

C. where, that                               D. which, where