Final answer:
The discovery service by OS X similar to DNS is called Bonjour. It facilitates automatic device discovery and service establishment on a local network without manual setup.
Step-by-step explanation:
The discovery service used by OS X that uses a name space similar to DNS is known as Bonjour. Bonjour, which was previously known as Rendezvous, is Apple's implementation of zero-configuration networking (zeroconf), which includes technologies such as multicast DNS (mDNS) and DNS service discovery (DNS-SD). This service allows devices on a local network to discover each other and establish network services without manual configuration. For example, Bonjour enables computers to locate printers, file-sharing servers, and other devices automatically on a network. The correct answer from the multiple-choice options provided is B) Bonjour.