Answer:
The answer is: B) People face trade-offs
Step-by-step explanation:
A trade-off happens when you have to balance two (or three in this case) opposing situations.
Rina has to decide how to divide the time she can spend training. If she chooses to do one activity, she can´t do the other. So she has to balance the time spent on each activity, probably depending on which sport she needs to train the most.