Sagot :
The answer is the option c. Uncle Frank is the one who will fix our plumbing. There is no need to use comma. Options A, B and D, introduce a split before who that is erroneous, because the clause after who is necessary to understand the meaning. You only use comme in front of who when you are introducing a clause that is not needed to understand the meaning.
the answer is C, you can tell because he has a green sheck