As local food gains popularity, farmers will attract more customers, leading to an increase in demand for the products they offer.
Nonrestrictive clauses are separated by commas within sentences. I would select the answer which as the right one because 'yet' links independent clauses, while 'that' and 'while' lead to restrictive clauses.
For instance:
The price, which I found quite high, was reasonable to Frank.
It could be either A or C, as Daphne exhibits greater confidence than Justin owing to her extensive experience and regular stage appearances.