Read the following paragraphs and answer the question.
But something unexpected happened. A patient who had been so depressed and could barely speak became ebullient after the 45-minute brain scan. Then a second patient, who seemed incapable of even a smile, emerged actually telling jokes. Then another and another. Was this some coincidence? Aimee Parow, the technician who made these observations (she is now a medical student in New York) didn’t think so. She mentioned the patients’ striking mood shifts to her boss, and together they completely refocused the study: to see if the electromagnetic fields might actually have a positive effect on depressive mood.
The word “ebullient” can be best replaced by（ ）.
A.正确答案Cinterested
B.quiet
C.excited
D.sorrowful
