Option 1 -> ephemeral means temporary or short-lived, not related to regularity or predictability.
Option 2 -> intermittent means occurring at irregular intervals, which is similar to erratic, not opposite.
Option 3 -> consistent means steady and unchanging, which is the direct opposite of erratic (irregular/unpredictable).
Option 4 -> supple means flexible or bendable, relating to physical properties, not behavioral patterns.
Hence, Option 3: consistent -> The antonym of erratic (unpredictable/irregular) is consistent (steady/regular). Her consistent behavior was surprising, likely because it contrasted with her typically unpredictable nature or the expected pattern -> correct