The publisher argues that shipping exercise and fitness books on time is crucial but not that it’s the "highest priority." The company can have higher priorities so long as it timely ships the books. Moreover, the conclusion only discusses shipping specific books, not all books.

The publisher doesn't make this argument. He concludes that shipping exercise and fitness books "on time" is crucial but doesn’t specify how to achieve it. The company might already be efficient, and the publisher could be reinforcing the need to maintain that efficiency.

The publisher does not make this argument. The publisher concludes the company "cannot afford to be outsold," but doesn't claim the company will be if it doesn’t match its competitors' organization. The company may not need the same level of organization to ship books on time.

This is a good summary of the argument’s main conclusion. The publisher concludes that it is necessary, or “imperative,” that the company ship its fitness and exercise books on time because it cannot afford to be outsold by its competitors.

The publisher does not make this argument. The publisher concludes the company must ship exercise and fitness books on time, not that it must follow its competitors' shipping practices. The company may already have better shipping practices that ensure timely shipping.