What word is best to substitute for the underlined words in the following sentence?
The man sat in the car waiting for the traffic light to turn green.

“The man” is singular, so the pronoun must be singular. It is also the subject in the sentence, so the pronoun must be in the subjective case.
“He” is singular and in the subjective case, so it is the correct answer.
“Him” is singular, but it is in the objective case.
“His” is singular but is a possessive pronoun.
“they” is in the subjective case, but it is plural.