In the competitive forces model, the central element that the other four elements contribute directly to strength is: a. risk of entry by a potential competitor. b. closeness of substitutes to an industry's products. c. rivalry among established firms in the industry. d. bargaining power of suppliers.

c. rivalry among established firms in the industry.

Explanation:

The Porter’s five forces of competition is a framework developed by Michael E. Porter in 1979, it is used to measure and analyze an organization's competitiveness in a business environment.

The Porter's five forces of competition framework are:

1. The bargaining power of suppliers.

2. The bargaining power of customers.

3. Threat posed by substitute products.

4. Threats posed by new entrants.

5. Threats posed by existing rivals in the industry.

In the competitive forces model, the central element that the other four elements contribute directly to strength is rivalry among established firms in the industry.

the answer is risk management planning