Pick the odd one out: water, wood, sound, air
The odd one out is sound.
Explanation: water, wood and air are all three states of matter; liquid, solid and gaseous respectively. But sound is a form of energy.
Pick the odd one out giving reason
(a) Eardrum, oval window, multiple refraction, auditory nerves
(b) Sound, water, vacuum, Steel, air
(c) Amplitude of vibration, quantity of vibrating air, frequency, decibel
(d) Hearing loss, high blood pressure, physical pain, noise