How likely is it that Carol will have a positive return on investment based on her educational path?

The rationale behind why A is the most fitting answer revolves around the financial aspect of Carol's situation. By spending less money during her first two years of education, she has managed to keep her initial investment lower than it could have been. This can result in a greater chance of achieving a positive return on investment once she enters the job market, particularly since she is already employed.

Employment indicates that she is likely applying her education in a way that generates income, which is crucial for recouping educational expenses. Additionally, the balance of lower initial costs and current employment positions her better to overcome challenges associated with student debt or potential negative impacts of transferring universities or needing further education.

This context highlights that the financial acuity in managing her educational costs and gaining employment contributes significantly to her likelihood of experiencing a positive return on her investment.