Which is correct?
__________ you hire will need at least three years of ASP.NET and AJAX development experience.
The answer is b.
These pronouns take a different case depending on whether the relative pronoun is used as a subject or an object. To determine whether to use who or whom, turn the sentence into a question. If you can answer the question with the word “he,” use who. If you can answer the question with the word “him,” use whom.*
Who/whom will you hire? You will hire him. (You wouldn’t say “you will hire he.”)
*An easy way to remember when to use who or whom is by noting that the word “him” ends in the letter “m.” So does the word “whom.”