Answer:
Option C. 4 Hz
Step-by-step explanation:
To know the correct answer to the question given above, it is important we know the definition of frequency.
Frequency can simply be defined as the number of complete oscillations or circles made in one second.
Considering the diagram given above, the wave passes through the medium over a period of one second.
Thus, we can obtain the frequency by simply counting the numbers of complete circles made during the period.
From the diagram given above,
The number of circles = 4
Thus,
The frequency is 4 Hz