Answer:
C. reward
Step-by-step explanation:
Basically, there are two types of motivation.
Intrinsic motivation is driven by internal reasons such as desire for knowledge, personal satisfaction, personal interests, hobbies, curiosity etc. It is important to note that here there aren't any external rewards which would act as a motivation.
On the other hand, external motivation is all about rewards such as money, fame, bet, praise, success, gain etc.
Gaining these external rewards drives people's actions and acts as motivation.