Clause 4.3 (Determining the scope of the ISMS) requires consideration of:

“the external and internal issues referred to in 4.1; the requirements referred to in 4.2; and interfaces and dependencies between activities performed by the organization, and those that are performed by other organizations.”

This confirms that dependencies between activities are a required factor when defining scope. Options B (quality levels), C (lessons learned), and D (regular activities for improvement) are not scope requirements, though they may be relevant in planning or improvement processes.

Thus, the verified answer is A: Dependencies between activities performed by the organization.