The question deals with selecting the right part of speech. There is a mix of adjectives and pronouns. In this case, the right pronoun is Which.
Inserted into the sentence, it reads, "The restaurant which Bob recommended was too expensive.
While pronouns are used in place of nouns, adjectives are used to qualify or modify a noun.
See more about parts of speech, pronouns, and adjectives in the links below:
https://brainly.com/question/721326
https://brainly.com/question/6651127
https://brainly.com/question/478396
