Why does the waitress agree to answer Bolsa's questions? because Sancho orders drinks
because she likes Bolsa
because she knows Mrs. Morningstar really cares about William

Because she knows Mrs. Morningstar really cares about William

Explanation:

Sancho and Bolsa are detectives who are looking for the missing William Morningstar. They come to a restaurant to talk to a waitress named Robin who might know William because he came to the restaurant where she worked often.

After some initial apprehension towards the men because she thought they worked for Jim Bob who she does not like, she opens up and begins to answer their questions when she hears that it was Mrs. Morningstar who hired them because she knows her and cares about William.