Answer:
during this story changing event
An adverb clause means that it has to be a full clause functioning like an adverb. This is the case in a): <span>Before you go to bed,
It's a clause (</span><span>"in our backyard garden| also has the function of an adverb but it's not a clause) and it's an adverb clause!</span>
Answer:
I think the answer is C (sorry if I'm wrong)
Explanation: