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. a. whom b. which c. that d. who

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 is option D. WHO

It is a non-defining realtive clause. Non-defining realtive clauses add extra information to a sentence by defining the noun. That can be used as a replacement of which or who in defining relative clauses.  But it is not correct to use THAT to replace shich /who in non defining realtive caluses