Which one of the following vignettes is best explained by classical conditioning?

Which one of the following vignettes is best explained by classical conditioning?

Sam hasn’t eaten all day. At about 3:00 in the afternoon, he is so hungry that all he can think about is a hamburger and fries

Latisha is 18 months old and she loves to play with her daddy when he comes home from work. When she hears his car pull into the driveway as usual, she gets very excited

Abraham is sitting in a coffee shop waiting for an important email to arrive in his inbox. He checks his phone repeatedly to see if the email has arrived.

Donna is sleeping soundly. The alarm clock next to her bed rings an alarm, and within seconds she is not only awake, but she remembers that she has a big test in just one hour