=+6. Students in a school are accustomed to moving to the next class when music plays. After a period of time, the princi- pal replaces the music with a bell to signal the end of class. If one day he plays the music by mistake and the students leave class, which of the following is being shown?

a. Acquisition

b. Generalization

c. Habituation

d. Spontaneous recovery

e. Operant conditioning