Directions: In the following sentence, three substitutions are given for each italicised part. If one of them is better than the italicised part, that should be your answer. If none of the substitution improves the sentence, the answer should be (4).

The artist continues to work the medium he understands best.

When describing an artist working with their materials, we use 'with' to indicate the instrument or medium being used. 'Work the medium' sounds like manipulating the medium itself, while 'work with the medium' correctly indicates using the medium as a tool for creation. This is the standard prepositional usage in artistic contexts.