Correct Answer: namesake

Solution : The correct choice is the third option.

Explanation: Namesake specifically refers to someone who shares the same name as another individual. It solely addresses the similarity in names between two individuals.

The meanings of the other options are as follows:

• Alias is a false or alternative name used by a person.
• Imposter refers to someone who pretends to be someone else to deceive others.
• Ancestor refers to a person from whom one is descended, typically several generations earlier.

Therefore, the correct answer is, namesake.