The correct option is D Sound wave 1 is louder than sound wave 2.
For a sound wave,
Loudness ∝ Amplitude and Pitch ∝ frequency.
From the graph given in the question, sound wave 2 has higher frequency than the sound wave 1. so the pitch of the sound wave 1 is less than that of the sound wave 2.
and amplitude of sound wave 1 is more than the amplitude of sound wave 2. So, the loudness of sound wave 1 is greater than the loudness of sound wave 2.
Thus, options (b) and (d) are the correct answers.