Interval training
a. can guarantee an athlete an injury-free season.
b. involves short periods of intense activity and is used to build strength, speed, and power.
c. involves long periods of low-intensity activity and builds stamina.
d. will get you into shape in about five days.

Well Interval training is training in which an athlete alternates between two activities, typically requiring different rates of speed, degrees of effort, etc. So in saying that, its not A, because nothing guarantee an injury free season, i dont hink it would be D either because that just doesn't seem reasonable, so its left up to B or C. But considering the definition for Interval training, it sounds more like B.

Aand b would both be correct

Olfactory epithelium i believe