Whomever is responsible for watching the little children at the park and making sure they don't run out into the road?

Question

What is the best way to write the underlined part of the sentence?
A.
Whom is responsible
B.
Which is responsible
C.
Leave as is
D.
Who is responsible

Answer 1

The best way to write the underlined part of the sentence is:

D. Who is responsible

The sentence would read: "Who is responsible for watching the little children at the park and making sure they don't run out into the road?"