Question

Make the following sentence more active: The test was completed by the student.

The test was quickly completed by the student.
The student was tested by the teacher.
The test was aced by the student.
The student completed the test.

Answer 1

I forget exactly what it's called, but what you need to do, basically, is make it so that the student is acting on the test, instead of the other way around.
We can immediately eliminate A and C, since they're basically the same thing, right?

B is still technically inactive, too ("The student was tested by the teacher," where it should be "The teacher tested the student.")

So your answer here is D- "The student completed the test" is the active form of that sentence.