Question

Steve made friends _____ later worked with him. which who

Answer 1

I would say who because it is calling for them in the context of who because they were just mentioned. 

Answer 2

Answer:

The correct answer is Who.

Explanation:

Relatives clauses make references to the noun that precedes them. There are different types of relatives clauses. The words given in this exercise are both relatives clauses. However, the relative pronoun "which" is used for things or animals and the relative pronoun "who" is specially used for people. So, in this exercise, the most correct relative pronoun to use is "Who"