According to the article, why is it difficult to publicize and market
POD books?

A. There are no excess materials stored in warehouses

Explanation:

It will be difficult to publicize and market "print on demand (POD)" materials because there are no warehouses were buyers can visit to purchase the excess materials stored at their convenience.

Actually, print on demand eliminate warehouses. This is because materials are printed whenever people order. So, it's likely things are done digitally. Even publication fees are paid online. So, with such in place, publicizing the material or marketing it becomes difficult.

the author is showing that it is the insatisfaction of basic needs that brings about the protests such as the strikes.if workers do not earn enough to buy food and feed their families and themselves in order to continue working, what is the use of working? besides, another message from the author is that of the owners of factories should be worried about ensuring their furure by having a second and third generation of workers in their industries.if they do not hear the workers demands, they will not have any more workers to make their pockets full.