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, <em>on the other hand</em>, my sister despises it.
"also" is being used to transition to another, similar thing. ex. The store <em>also</em> 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.
