What is a key architectural consideration when implementing "zero trust" security models in enterprise IT infrastructure?

A Continuously verifying the identity and trustworthiness of every user and device, regardless of whether they are inside or outside the network perimeter, before granting access B Trusting all devices and users inside the corporate network perimeter by default C Eliminating the need for any authentication once a user logs in once D Relying solely on a single perimeter firewall for all security needs