Answer:
Air.
Explanation:
To know which option is correct, let us consider the relationship between velocity and the wavelength of a wave. This is illustrated below:
Velocity, wavelength and frequency are related by the following equation:
Velocity = wavelength × frequency
v = λf
From the equation above, we can see clearly that the velocity is directly proportional to the wavelength.
This means that an increase in the wavelength will lead to an increase in the velocity and also, a decrease in the wavelength will lead to a decrease in the velocity.
Now, considering the table given in the question above, we can see that the wave has a higher speed in air. This simply means that the wave will also have a higher wavelength in air.
Thus, the correct answer to the question is: air
