The number of communication channels in a project is an indicator of the complexity and difficulty of managing the communication among the stakeholders. The more stakeholders there are, the more communication channels there are, and the more challenging it is to ensure effective and efficient communication. The number of communication channels in a project can be calculated using the following formula: Number of communication channels=n×(n−1)/2 where n is the number of stakeholders. In this case, n=65, so the number of communication channels is: Number of communication channels=65×(65−1)/2 Number of communication channels=65×64/2 Number of communication channels=4160 Therefore, the correct answer is A. 4160.Reference: CCBAHandbook, p. 15 Number of Communication Channels (+ PMP Formula & Calculator), section "Formula to Calculate the Number of Communication Channels"