Concept:"Explicit" means clear and detailed, so its opposite should mean unclear or indefinite.
Explanation:An explicit explanation is stated clearly and precisely.
It leaves no room for confusion or doubt.
The sentence shows that Mary's explanation was explicit, but mine was the opposite.
"Vague" means uncertain, indefinite, or unclear in meaning.
Thus, "vague" is the closest opposite of "explicit" and correctly fills the gap.
"Long" suggests length, "winding" suggests indirectness, and "irrelevant" suggests lack of connection.
None of these directly oppose the meaning of "explicit."
Answer:C. vague