In each of the following sentences four words or phrases have been underlined. Only one underlined part in each sentence is not acceptable in Standard English. Find out that part and darkens the circle having its number 1, 2, 3 or 4 in your Answer Sheet.
Our strongest(1) reason for siding(2) with(3) the Communists is because(4) our father is a Communist.
Option D is the answer as the correct way to phrase it would be "that" our father is a communist.