D. 16.8 units
A radius is half of the diameter, so to get the answer all you need to do is multiply the length of the given radius by 2.
8.4x2= 16.8
Answer:
D
Step-by-step explanation:
If a function has x in the denominator, it cannot be a polynomial.
The rest of the options either don't apply to the equation, or are not rules for polynomials.
$3.00 I think. Hope this helps