An administrator brings the company's fleet of mobile devices into its PKI in order to...

Comprehensive and Detailed Explanation:

For bulk PKI enrollment:

MDM integration with directory services streamlines certificate request and deployment per device, leveraging existing authentication methods.

Simple Certificate Enrollment Protocol (SCEP) with one-time passwords allows automated, secure, large-scale certificate issuance without manual CSR handling.

clientAuth templates are used for device authentication, but selecting it alone is insufficient without automated enrollment mechanisms.

A single certificate for all devices violates PKI security principles and compromises individual device accountability.