Select the option that can be used as a one-word substitute for the given group of words/phrase.

Rarely; not often

seldom

The word that can be used as a one-word substitute for "rarely; not often" is seldom.

• Habitually means done regularly or customarily.
• Seldom means not often or rarely.
• Frequently means many times in a short period of time.
• Routinely means in a regular or habitual way.

Seldom is the most appropriate word for the given group of words because it specifically refers to something that happens infrequently or rarely. It is derived from the Old English word seldan, meaning "not often."