The most comprehensive answer to the question regarding what is most important in planning and financial management competency is:
C. (a) and (b)
Both mathematical knowledge and time management are crucial in effectively managing finances and planning. Mathematical knowledge is necessary for budgeting, financial analysis, and forecasting. Time management is equally important as it helps in prioritizing tasks, meeting deadlines, and ensuring that financial plans are executed efficiently. Therefore, both competencies are essential for successful planning and financial management.