Option 1 states that both statements are individually true and that statement II is the correct explanation of statement I. Let`s analyze this.

Statement I says that the pitch of a sound wave depends on its frequency. This is correct because pitch refers to how high or low a sound is, and frequency is directly related to the perceived pitch of a sound. Higher frequency waves have a higher pitch, while lower frequency waves have a lower pitch.

Statement II says that the loudness of a sound wave depends on its amplitude. This is also correct because amplitude refers to the maximum displacement of particles in a sound wave, and it directly affects the intensity or loudness of the sound. A larger amplitude creates a more intense and louder sound, while a smaller amplitude results in a softer sound.

Therefore, both statements are true individually. However, statement II is not a correct explanation for statement I. While both frequency and amplitude affect different aspects of sound waves (pitch and loudness respectively), the relationship between the two is not one of explanation. Thus, Option 2 is the correct answer.