BYOD, or Bring Your Own Device, is the correct answer because the company is allowing employees to use personally owned devices to access internal company resources such as email. In Security+ architecture and operations topics, mobile deployment models are important because each model shifts ownership, management, and risk differently. BYOD reduces hardware procurement costs, but it increases security concerns because the organization does not fully own or control the endpoint. Controls such as MDM, conditional access, encryption, remote wipe, acceptable use policies, and device compliance checks are commonly needed. CYOD means employees choose from approved corporate devices, while COPE means the company owns the device and permits personal use. MDM is a management control, not the deployment strategy itself.