Final answer:
The best exemplification of someone being encumbered is a student who has too much homework and thus can't watch a movie. The term 'encumbered' signifies being heavily burdened or restricted in movement or progress.
Step-by-step explanation:
The best example of someone who is encumbered is C. A student misses a movie because she has too much homework. The term encumbered refers to being hindered or burdened, especially in a way that makes movement or progress difficult.
In the case of the student, the excessive amount of homework is the burden that prevents her from doing a more enjoyable activity, like watching a movie. This aligns with the core meaning of being encumbered as one's ability to act freely is restricted by a heavy load, whether literal or figurative.