the central idea is that munda leaves home and then further become aware of the abuse around her
I would go with the last sentence.
The question is whether those phrases are speaking of the same person :
<span>A. her friend and former room-mate
- this is the same person, if it was two people, it'd be "and her"
B. </span><span>the winner and still champion
-again, the same person, requires singular verb
C.</span><span>The chief and foremost expert
-again, the same person: requires a singular verb and actually has a singular verb, correct answer!
</span>
B. Is correct. Here is why.
A. Is true because a normal sentence contains 1 clause. A compound contains two.
C. You will always need a comma and a coordinating conjunction.
D. Could possibly be correct depending on what you are writing.
Have a nice day!