Classical conditioning is defined as learning process in which two stimuli is linked togather to generate a response. Biologically influential and strong stimuli is subjected with formerly neutral stimuli.
According to the question, as Stephanie has got many penicillin injections from doctor , she recognizes that injections received from white-coat people(doctor) give her pain. Due to this learning, she recognized white coat photographer as doctor who will give injection and thus, started to cry
