Although robots will one day help with household chores, it will never completely replace human cleaners.
А NO CHANGE
B they
С he
D you

B

Explanation:

Robots are objects so they don't get identifying pronouns, but the sentence is talking about for than one so you would say they.

hancock was president of congress when the declaration of independence was adopted and signed. he is primarily remembered by americans for his large, flamboyant signature on the declaration, so much so that "john hancock" became, in the united states, an informal synonym for signature.

explanation: