Answer:
"As a result" signals a transition that shows a cause-and-effect relationship.
for ex. My brother did not attend school yesterday because he was feeling sick. As a result, he now has to make up an English test he missed.
Explanation:
"On the other hand" is used to contrast two things. ex. I like the color purple, on the other hand, my sister despises it.
"also" is being used to transition to another, similar thing. ex. The store also had those snacks you enjoy, so I bought them.
"before" doesn't always mean it relates two events with a cause/effect relationship. ex. I locked the front door before we left for dinner.
