When Light Bulbs Were First Introduced,manufacturers Offered One Size for All

Multiple Choice

When light bulbs were first introduced,manufacturers offered one size for all light fixtures.Today you can buy light bulbs in different shapes,different wattages,and different colours.They also differ as to how much electricity they use and their duration.Which of the following BEST describes light bulb manufacturers?

A) They are aiming at a goal of profit through maximum sales volume.
B) They are sales-oriented companies.
C) They miss sales by not concentrating on the average customer.
D) They recognize that different customer groups have different needs and wants.