How to define period, frequency and amplitude with examples?

The Period goes from one peak to the next (or from any point to the next matching point)

The Amplitude is the height from the center line to the peak (or to the trough). Or we can measure the height from highest to lowest points and divide that by 2.

The Frequency is how often something happens per unit of time (per "1")

It is d, all the other ones say incorrect answer .