Answer:
Option 2nd is correct
r = 8 units
Explanation:
As per the statement:
The formula for the circumference of a circle is C = 2r
where, r is the radius of the circle
To find the radius of the circle.
Circumference(C) = 16 units
then;

Divide both sides by 2 we have;
8 = r
or
r = 8 units
Therefore, the radius of the circle is, 8 units