Nancy Is Reviewed Her Billing Summary for Her Google AdWords

Multiple Choice

Nancy is reviewed her billing summary for her Google AdWords account. There is a line item in the billing summary titled 'Adjustment - Click Quality'. What does this line item mean?

A) Nancy has been credited for clicks on her ad that were deemed invalid clicks.
B) Nancy has been credited for clicks on her ad that took longer than five seconds to resolve.
C) Nancy has been credited for clicks on her, for Google incurred cost overruns for displaying her ad beyond her given budget.
D) Nancy has been credited for clicks on her ad that didn't take visitors to her domain.