Respuesta :
The amount of $840 will be extra money one will have to invest each year if you are not paying interest on that credit card debt.
What is a credit service?
This is a loan service provided by credit firm to an individual, business etc which is expected to be repaid with interest.
Extra money = $4,000 * 21%
Extra money = $840
Therefore, the Option B is correct.
Read more about credit service
brainly.com/question/14456635
#SPJ2