the correct answer is (e) which is all of the above.
Explanation: Customers are king, their satisfaction is the ultimate goal for a business. Unsatisfied customer are difficult to retain as well, hence, their problems must always be welcomed and solved. It also aware the firm or give an idea about what needs to be changed or added. Negative word of mouth is also prevented. Its a chance for an organization to convert dissatisfied customer into highly satisfied customers and chances of retention increases as well.