Which of the following could replace 'continuum' as used in the passage?

Directions: Read the following passage carefully and select the most suitable option according to the corresponding number in the passage.

For those pursuing a bachelor’s degree in security, it is important to understand the basic components of crisis management. A bachelor’s degree in security suggests the degree holder has a comprehension of tactics and tools which would assist in the asset protection of an organisation. Much of that knowledge is likely to be focused on physical protection systems, liabilities, and security’s role in the organization.
Crisis management, sometimes referred to as incident management, is a field of study in which practitioners attempt to stop the emergency situation or at least reduce its negative impact. This mitigation comes via threat assessments, planning, training, incident response, and continuation of operational duties.
The continuum of services is essential to the emotional and financial well-being of an organization.