The correct option is A Uninventive
The word 'ingenious' refers to a person who is original, clever and inventive.
Option A, uneducated refers to having or showing a poor level of education.
Option B, uninventive refers to not showing creativity or original thought.
Option C, unintelligent refers to having or showing a low level of intelligence.
Option D, untrained refers to not having been trained in a particular skill.
Thus, according to the meaning, the word 'uninventive' is the farthest in meaning from the word 'ingenious'.