When developing an exercise programme, it is important to include:

In CBCI 7.0, exercising sits within Validation (PP6) and is used to confirm that plans, procedures, and response structures can achieve the objectives set by the BC policy and BCMS requirements. An exercise programme must therefore be designed around the scenario and the capabilities being validated—meaning the correct participants are those who would actually perform roles during that type of disruption (strategic decision-makers, incident/crisis team roles, operational recovery leads, communications, IT/service owners, and key support functions), plus any dependent parties as needed.

That is exactly what option D states: include everyone with a role in a team relevant to the scenario being exercised. Including all employees (A) is unnecessary and often counterproductive; awareness activities can target all staff, but exercises should be role-based and objective-led. Including only the response team (B) excludes essential recovery and support roles that are frequently critical to product/service restoration. Including only BC professionals (C) turns an organizational capability test into a specialist discussion and fails to validate real execution.