Option 1 -> Brilliant means exceptionally talented or outstanding, which is the opposite of mediocrity.
Option 2 -> Average means ordinary or moderate in quality, which accurately captures the meaning of mediocrity.
Option 3 -> Middle refers to a central position or location, not a quality level or standard.
Option 4 -> Very poor indicates extremely low quality, which is worse than mediocrity (mediocrity suggests ordinariness, not poorness).
Hence, Option 2: Average -> Mediocrity describes the state of being mediocre or of moderate to low quality—neither excellent nor terrible, but rather ordinary and unremarkable, which is precisely what "average" conveys -> correct