Answer: 1st wave
Explanation:
The higher the frequency of the wave , higher the pitch.
To find the highest-pitched sound we should find the wave with the highest frequency.
wave's frequency is the number of cycles that are completed in a certain amount of time
If we consider the number of oscillations in a given time of 0.01 seconds , wave 1 has the highest number.
therefore wave 1 has the highest frequency , so the pitch.