All three, the frequency, wavelength and velocity are associated with the whole wave while the amplitude is associated with the constituent particles of the wave undergoing simple harmonic motion. So, option a is correct.

Properties of a wave:

A wave is a disturbance that travels through space and time, transferring energy from one point to another. Waves have various properties that determine their behavior:

1. Amplitude: The maximum displacement of a wave from its equilibrium position is known as its amplitude. It is measured in meters (m) or other units such as volts (V) or decibels (dB).

2. Frequency: The number of cycles a wave completes in one second is known as its frequency. It is measured in Hertz (Hz) or cycles per second (cps).

3. Wavelength: The distance between two successive crests or troughs of a wave is known as its wavelength. It is measured in meters (m) or other units such as nanometers (nm) or angstroms (Å).

4. Velocity: The speed at which a wave travels through a medium is known as its velocity. It is measured in meters per second (m/s) or other units such as kilometers per hour (km/h) or miles per hour (mph).

Differentiating factor:

The one property that is different from the others is amplitude. Here's why:

1. Amplitude is a measure of the intensity or strength of a wave, whereas frequency and wavelength are measures of its size and shape.

2. Amplitude does not affect the speed of a wave, whereas frequency and wavelength do. This is because the speed of a wave depends only on the properties of the medium through which it travels.

3. Amplitude can vary widely depending on the source and the medium through which the wave travels, whereas frequency and wavelength are fixed properties of a wave that depend only on its source.

In conclusion, while amplitude is an important property of a wave, it is different from frequency, wavelength, and velocity in that it measures the intensity or strength of a wave rather than its size, shape, or speed.