Option 1 -> Sleepy means drowsy or inclined to sleep, which is exactly what somnolent means.
Option 2 -> Fainted means to lose consciousness suddenly, which is different from being drowsy or sleepy.
Option 3 -> Weak refers to lacking physical or mental strength, not specifically related to sleepiness.
Option 4 -> Happy is an emotion expressing joy or contentment, completely unrelated to the state of drowsiness.
Hence, Option 1: Sleepy -> Somnolent is derived from the Latin word "somnus" meaning sleep, and directly translates to drowsy, sleepy, or lethargic -> correct