A random sample of 45 door-to-door salespersons were asked how long on average they were able to talk to the potential customer. Their answers revealed a mean of 8.5 minutes with a variance of 9 minutes. What is the point estimate for the average conversation length?a. 45 salespersonsb. 9 minutesc. 8.5 minutesd. 5 minutese. None of the above