An excellent, inexpensive, and readily accessible method for assessing customers' service expectations is
a. customer complaints.
b. syndicated data services.
c. employee empowerment programs.
d. distributive fairness analysis.
e. management by objective programs.

a. customer complaints .

Explanation:

Customer complaints -

It refers to the problems or dissatisfaction faced by the customer regarding any of the product or services , is known as customer complaints .

This complaints helps the company or the organisation , to get the feedback of the product from the customer and to helps the company to improve or alter the product so as it make it more useful for the consumer and , which in turn will increase the production and profit of the company .

Hence , It is considered to be most appropriate  , inexpensive method to deal with any problem .