Answer: The correct answer is amplitude.
Step-by-step explanation:
Transverse wave is defined as the wave which travels perpendicularly to the direction of energy transfer.
A wave can be defined using 3 parameters: Frequency, wavelength and amplitude.
Frequency is defined as the number of oscillations happening in one second.
Wavelength is defined as the distance between two successive crests or troughs in a wave.
Amplitude is defined as the vertical line from the equilibrium position to the midpoint of the crest or a trough.
Hence, the correct answer is Amplitude.
The wave is shown in the image below.