Elle se brosse les dents d’aller se coucher.

Explanation

The correct answer is avant
The correct sentence would be: "Elle se brosse les dents avant d'aller se coucher." Which translates to "She brushes her teeth before goin to bed."
"Avant" is a preposition that indicates an action that occurs before another action, in this case, brushing her teeth happens before going to bed.
Note: The option "avarit" is not a French word, it seems to be a typo. The correct answer is "avant".