TSA CBT Practice Test 2025 - Free TSA CBT Practice Questions and Study Guide.

The word "or" is indeed classified as a conjunction. Conjunctions are words that connect clauses, sentences, or words in lists. "Or" specifically is a coordinating conjunction used to offer alternatives or choices between options.

The other words in the list serve different grammatical functions: "happy" is an adjective describing a noun, "quickly" is an adverb that modifies a verb, and "under" is a preposition indicating a relationship in terms of location. Thus, "or" is the correct choice as it fits the definition and function of a conjunction.