Read this sentence:
To become certified, you must take a written exam, have taken a physical activity test, and submit to a background check.Which revision of the sentence uses parallel structure?

A.To become certified, you must be taking a written exam, take a physical activity test, and submit to a background check
. B.To become certified, you must take a written exam, take a physical activity test, and submit to a background check.
C.To become certified, you must take a written exam, taking a physical activity test, and submit to a background check.
D.To become certified, you must take a written exam, take a physical activity test, and to submit to a background check.