Final answer:
The principal, being the original amount borrowed or charged before interest, is $500. As this is the cost of the TV before the added interest that made the total payment $600,
option c is correct.
Step-by-step explanation:
The principal in a loan or credit transaction is the initial amount of money borrowed or the amount of the debt minus the interest charged. In this situation, you were charged $500 to your credit card to buy a new TV and you paid off a total of $600 after six months, with the additional $100 being the interest accrued over that time. Therefore, the principal amount, which is the original amount charged for the TV, is $500.
The term 'principal' is used in finance to refer to the original sum of money borrowed in a loan or put into an investment, excluding any interest or profits. In the case given, the $500 is the original amount that was put on the credit card, which is the principal amount.
So, the correct option is c. $500.