"His wife, Eleanor, who he relied on for advice and support, urged him to remain involved in politics." is the correct sentence.
Nominative pronouns function as the subject of the sentence. This is why they are also known as subjective pronouns. Common nominative pronouns are I, you (both singular and plural), he, she, it, we, they and who.
Objective pronouns are used when something is being done to the subject. Common objective pronouns are me, you (both singular and plural), him, her, it, us, them and whom.
In the given sentence, the correct pronoun is "who". It is a nominative pronoun.
The subject in this sentence is Eleanor, and since the pronoun refers to her, it has to be nominative. Of the given options, "who" is the nominative pronoun and thus it is correct.
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brainly.com/question/1575851