The correct option is
C Define the period of an exponential function
- When a function repeats its values at regular intervals or periods is known as a periodic function.
- The particular interval after which a function repeats its values is called the period of the function.
- The graph of an exponential function is given along.
- The graph depicts that an exponential function is periodic and have a purely imaginary period .
![](https://byjus-answer-creation.s3.amazonaws.com/uploads/01.png_img_upload_solution_2022-06-01 10:54:58.363372.png)
Thus, the period of the exponential function is which is imaginary.
Hence, option (C) is the correct option.