Question

Select the correct relative pronoun to complete this sentence. Alchemists​,​ _____ wanted to transform base metals into​ gold, were also among the first people to conduct laboratory​ experiments.

Answer 1

The correct relative pronoun is who

Answer 2

who

Who best fits in the blank. The best way to choose between who and whom is to replace it with he or him. In this sentence it makes sense to say "He wanted to transform.." It does not make sense to say "Him wanted to transform". Since he is the best fit, who is the best relative pronoun.