The commas must be placed both before and after the nonessential element. For example...
My mom, who hates cooking, ordered takeout.
"who hates cooking" is the nonessential element, and you can see that a comma goes before and after it.
Answer: having second thoughts about her new job
Explanation:
Wavering means to be doubtful, unsure or uncertain about a particular thing. Someone who wavers is said to falter as the person is faced with an indecision.
When the narrator says "I was wavering in my secret soul", she means that she was having second thoughts about her new job.
Therefore, the answer is option D.