Kerri hands a guest a room key, smiles, and says, "If we can do anything to help make your stay more pleasant, don't hesitate to call us." A trainer in the background makes some marks on a paper on a clipboard. A training program that emphasizes the degree of sincerity or friendliness with which guest service is delivered is likely based on which of the following types of training objectives?

a. on-the-job behavior
b. learning-acquired
c. critical-incident
d. reaction-based