Select the most appropriate option to fill in the blank.
He is ______ poorer than all his friends.

Correct option is A

The correct option to fill in the blank is (a) "much."
"Much" is used to emphasize a comparative adjective, in this case, "poorer."
Meanings of other options:
• Most: Used for the superlative degree, not appropriate here.
• More: Used for comparative degree, but not with "poorer."
• Very: Used to emphasize an adjective, but not in comparative forms.