Which of the following is correct?

• A. Semivariable costs remain fixed for a while and then rise sharply to a higher level as a higher output is produced.
• B. Salaries paid to production supervisor can be an example of semivariable cost.
• C. Semivariable costs has no effect on break-even analysis.
• D. All of the above is correct.
• E. Only a and b are correct.