Answer:.a. external rewards; reduce any inherent intrinsic interest
Step-by-step explanation:
External rewards refers to the rewards that are given to someone in order to encourage a particular behaviour like the principal above is planning to implement a program where students can read for cash , this cash comes as an external reward with a hope to encourage reading.
Intrinsic value or intrinsic interest refers to the character or nature of something which makes it appealing in no association to other things.