A slow-witted and incompetent person

A. Nigger

B. Dud

C. Snotty

D. Duffer

Answer: Option D

Solution(By Examveda Team)

One word substitute is Duffer.

Nigger: a contemptuous term for a black or dark-skinned person.
Dud: a thing that fails to work properly or is otherwise unsatisfactory or worthless.
Snotty: full of or covered with nasal mucus.
Duffer: an incompetent or stupid person.