Concept: Stress pattern refers to which syllable is pronounced with the most emphasis in a word.Explanation: The words "maintenance", "candidate", and "primacy" all place their primary stress on the first syllable.For example, "can-di-date" has stress on "can".However, "enigma" places its primary stress on the second syllable: "e-nig-ma".Therefore, "enigma" follows a different stress pattern from the rest.Answer: C. enigma