i am the person .......................(whom / who / that) is to blame.
explain with reason.
“Who” is used as a subject and “whom” is used as an object. In the sentence we need a replacement for the noun clause “I am the person” that is a subject. Hence, the correct answer is “who” and not “whom”.
“Who” and “whom” are used for living things.
“That” and “which” are used for non-living things.