Which of the following joins two clauses of a sentence:

In grammar, a conjunction is a word that connects words, phrases, or clauses. Clauses are fundamental units of a sentence containing a subject and a verb. Conjunctions like 'and', 'but', 'or', and 'because' are crucial for forming complex and compound sentences by linking these clauses.

• 'Conjunction' is correct as its primary function is to join grammatical units, including clauses.
• 'Adjective' modifies nouns or pronouns, describing their qualities.
• 'Noun' names a person, place, thing, or idea.
• 'Article' (a, an, the) specifies or generalizes nouns. None of these parts of speech serve the primary function of joining clauses.