please answer this econ question. Thank you!

Question 3 1 pts Which of the following would be considered an explicit cost of production? O The repayment of your small business loan plus interest O The foregone interest you would have earned on the money you took out of your investment portfolio to start your business O The salary you would have earned on the job you quit to start to your business O The foregone rent you could have earned on your building if you rented it out instead of using it to start your business