Hello, Hanuman
"The person
whom I admire" is the grammatically correct form.
Also correct is the same structure without the relative pronoun: "The person I admire".
By the way, the subject of your thread is "verb", but your question is about pronouns (relative pronouns): "who" and "whom".
If you'd like to have a more detailed explanation of the use of "who" and "whom", you can have a look at
this thread.
Hope it helps.
Miriam