Jennifer recently bought a new computer to type a new manuscript she's been working on$.$ She also stored a lot of movies on it to watch during her free time. Though the performance was good at the beginning, it deteriorated quickly over a small period of time. Which of these is the most likely cause?

Declining clock speed of the core processor

Dysfunctional AC adapter

Declining free space on the hard drive

Fault plug$-$n$-$play devices like USB flash drives