Well… from what I know adjectives help describe something specifically, like:
“Very good” instead of just “good” or “She was so adorable.” with “adorable” being the adjective, etc.

In this sentence the word “teenagers” is your subject considering the sentence revolves around them (from what I can tell) which would mean the only words particularly describing who the teenagers are would be A. “most” and “Danish”. Or at least that is what I would assume. B. could be the answer as well considering that Danish describes that the teenagers are Danish and English further indicates that they speak some English.

Anyhow, hopefully that helps in someway, I am not the greatest at English… ^^; – Have a great rest of your day!