The correct pronoun in the above case is “we” because the other words such as “us”, them and ourselves used phrase modification.
The correct grammatically fluent sentence is formed in the above case, i.e. “we thought the movie was very good”.
Thus, the options (c), (d) and (a) are incorrect.
The correct grammatically fluent sentence is formed in the above case, i.e. “we thought the movie was very good”.
Therefore, the correct option is – b. we.