Read this sentence from paragraph 6 of the passage.

"Yet scientists have known for a long time that teens need around nine hours of sleep each night—that is, if they want to function at their best."

Which of the following could best replace the word "function" in this sentence?

A. maintain
B. achieve
C. perform
D. practice

Reading Passage
"8:30 Should Be the New 7:30" by Ravi Singh

It is 7:30 a.m. at a high school in New Orleans, and Carrie Guidry slides into her desk in her English class. The teacher begins a discussion on an author Carrie really likes. Yet five minutes later, the freshman's eyelids start to droop and her head begins to nod.