The movie was intriguing. a. who we saw last month c. that saw last month b. that we saw last month d. that we seeing last month

The movie that we saw last month (B) was intriguing.

Explanation:

This sentence also become meaningful by aptly filling the blank with ‘that we saw last month’. This is because the sentence already contains the tense was which hints that the movie was seen in the past. Thus, the choice of words "that we saw last month" is precise and relevant with the sentence and the tense. Moreover, "that" is used because this is the thing which has been done earlier.