Four-year-old Della asks her mother for a special treat every time they go to the grocery store. Although at one time her mother granted every request, she now does so less consistently. Research suggests that Della will: 

a. come to ask for a treat only occasionally.
b. soon give up asking for a treat entirely.
c. ask for a treat every time her mother takes her out, even if they don't go to the grocery store.
d. continue to ask for a treat nearly every time she goes to the store.