D because it combines the sentences correctly. I think, I'm puzzled between d and a but I really do think its d. :) Hope this helps!
What is the question to this?
Answer:
Be cause it help to better know the information you need
Explanation:
A simple sentence consists of only 1 clause. examples: 1. Joe waited for the train. 2. the train was late. 3. Fred and Dobby took the bus.
What? Are you even asking a question? Sorry if you took that as rude!