Adding the prefix de- to the word value makes a word that means

1."lessen the worth of ."
2."increase the worth of."
3." beyond the worth of."
4."against the worth of ."

1."lessen the worth of ."

When you devalue something you lessen the worth of it. For example, if you get into an accident with the car, you will reduce it's value. We also know that the prefix de- means to go down. For example, when you descend in an elevator you are going down to a lower floor.

the answer should be b.

explanation:

it should be b because she researched before writing so it would be in past tense. "the author researches her subject before she had written the first draft.