Answer: The answer is (d) the circumference is found by multiplying pi by the diameter.
Step-by-step explanation: We are to select the correct statement from the given options that are true about the circumference of a circle.
We know that the circumference 'C' of a circle is given by

Where 'r' is the radius of the circle.
So, 2r = diameter of the circle.
Therefore, the circumference is found by multiplying pi by the diameter of the circle.
Thus, (d) is the correct option.