The common method of breaking larger network address space into smaller networks is known as:

A.
subnetting.

B.
phishing.

C.
virtualization.

D.
packet filtering.

Explanation:
Subnetting is a dividing process used on networks to divide larger groups of hosts into smaller collections.
Incorrect Answers:
A: Phishing is a type of social-engineering broadcast attack that concentrates on pilfering credentials or
identity data from possible targets.
B: Virtualization allows a single set of hardware to host multiple virtual machines.
C: Packet filtering is used to regulate network access by monitoring outgoing and incoming packets and
allowing them to pass or be blocked based on the source and destination Internet Protocol (IP) addresses,
protocols and ports.

Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 39, 40, 120
https://www.techopedia.com/definition/4038/packet-filtering