Explanation:

A market segment consists of a group of customers who share a similar set of needs and wants. Thus we distinguish between car buyers who are primarily seeking low cost basic transportation, those seeking a luxurious driving experience, and those seeking driving thrills and performance. We must be careful not to confuse a segment and a sector. A car company might say that it will target young, middle-income car buyers. 
A flexible market offering consists of two parts: a naked solution containing the product and service elements that all segment members prefer and discretionary option that some segment members like. Each option might carry an additional charge.

For example, Delta Airlines offers all economy passengers a seat and soft drinks. It charges economy passengers extra for alcoholic beverages. Siemens Electrical Apparatus Division sells metal-clad boxes to small manufacturers whose price includes free delivery and a warranty, but also offers installation, tests, and communication peripherals as extra-cost options.