While there is a positive relationship between customer satisfaction levels and the speed with which a firm responds to customer problems, empirical research using American Customer Satisfaction Index $($ASCI$)$ data uncovered an important finding regarding response times and customer satisfaction. Which of the following best sums up the ASCI's findings about satisfaction and response times for customer problems?

a firm's response time to problems is the driving factor behind high customer satisfaction levels

actually resolving customer problems trumps response time

customers generally give firms a $72$ hour window to respond to problems before customer satisfaction drops

customer expectations for response times have remained stable for just over two decades