Which of the following BEST describes the need for implementing a compensating control?

a$.$

A recent data loss due to a server failure and lack of a data backup and recovery plan.

b$.$

A large number of network intrusion attempts going unnoticed due to a defective IDS.

c$.$

Unauthorized access to the server room due to IT technicians leaving the door ajar.

d$.$

The firewall recommended by your CTO is extremely expensive and complicated to configure.