Umberto is using Duo Lingo to learn how to speak Japanese. Every time he gets a question wrong, he loses a heart, but each morning, at 7am, his hearts are fully restored and he can play again. He has to log in to get access to the hearts, but they replenish at the same time every day. What schedule of reinforcement best describes this scenario?
a. VR
b. CRF
c. FI
d. FR