The next step which Heather should take after she has gotten a fraudulent call asking for her credit card details is to hang up and call her credit card company using the 1-800 number on the back of her card to inquire about the issue or report the attempted phone fraud.
As a result of this, we can see that Heather was a target of an attempted phone fraud where a caller asks her to give her 16-digit credit card details so that the supposed error could be cleared up.
It is worth noting that this information can be used to steal money from her checking account and Heather would best not give out such sensitive details over the phone, but call the company to see if the call is really from them.
Therefore, the correct answer is option C
Read more about phone fraud here:
https://brainly.com/question/8969110