An exponential function has an initial value of 500 and a decay rate of 15%. Compare the average rate of change for the interval 0

The answer is letter A. 
In the paragraph, only 20% of the customers who voted highly returned. From this, we can only say that some of those people came back. Most means a majority of the population and some means a minority. 
Also, we can't say C or D because we do not have any information regarding customers who voted badly. C says that high rating make people come back, but we do not have any information on the people who voted mediocre. We can not say C. D says that customers who come back will be high rating customers. We do not know if any customers who voted low came back, so we are unable to say D.