Fill in the blank with the most appropriate option:

She completed the assignment ____ her friends were still brainstorming ideas.

Option A is the correct answer.

Option A: "While" indicates two actions happening simultaneously. This fits perfectly because her friends were brainstorming at the same time she completed the assignment.

Option B:  "Whenever" implies repeated occurrences or any time something happens. This does not fit because the sentence describes a specific instance.

Option C: "Where" refers to a location, which is unrelated to the temporal connection between the two actions.

Option D: "As soon as" implies immediacy, meaning one action happens directly after the other. This does not work because the sentence describes two actions occurring concurrently, not consecutively.