Who vs. Whom 

Rule.

Use the he/him method to decide which word is correct.
he = who
him = whom

Examples:

• Who /Whom wrote the letter?

He wrote the letter. Therefore, who is correct.

• For who/ whom should I vote?

Should I vote for him? Therefore, whom is correct.

• We all know who /whom pulled that prank.

This sentence contains two clauses: We all know and who/whom pulled that prank. We are interested in the second clause because it contains the who/whom . He pulled that prank . Therefore, who is correct. (Are you starting to sound like a hooting owl yet?)

• We want to know on who/ whom the prank was pulled.

This sentence contains two clauses: We want to know and the prank was pulled on who/whom . Again, we are interested in the second clause because it contains the who/whom . The prank was pulled on him. Therefore, whom is correct.