Choose the antonym of Vague

Choose the antonym of Vague
A: Known
B: Clear
C: Popular
D: None of these

Vague means not clearly expressed. The opposite sense is clear which signals definite meaning and sharp boundaries. Known relates to familiarity not precision. Popular refers to favor not clarity. Antonym tasks focus on the core semantic axis. Hence pair vague with clear for a direct contrast that matches dictionary definitions.