One who cannot read and write is:

Correct option is B

The correct one-word for the given group of words is (b) Illiterate.
Correct word: Illiterate – A person who is unable to read and write.
Hindi meaning: अशिक्षित, निरक्षर
Use in a sentence: The new literacy program aims to educate the illiterate population in rural areas.
Meanings of the other options:
· (a) Illegible – Not clear enough to be read.
Hindi: अपठनीय
Example: The handwriting on the note was so illegible that no one could understand it.
· (c) Illegal – Against the law; not permitted by rules or laws.
Hindi: गैरकानूनी
Example: Selling banned substances is illegal.
· (d) Illicit – Forbidden by law, rules, or custom; usually refers to morally wrong or secret activities.
Hindi: अवैध, अनुचित
Example: He was arrested for his involvement in illicit trade.