According to the Textbook, Why Has Sales Work Increased Over

According to the textbook, why has sales work increased over time?

A) New technology, such as the "intelligent" cash register, necessitate more jobs in sales.
B) Workers have been displaced from shrinking farming and precision craft occupations into sales jobs.
C) Improvements in transportation and communication and increases in disposable income have increased markets.
D) Department stores have displaced specialty stores and provided many more jobs in sales.
E) Direct sales workers create jobs for themselves when other jobs are unavailable.