The domain are the required input for a given function, while the range are the output or result from the function.
So what is the question exactly I’m confused on how this is asked
The answer should be 1.80
For this case we have that the cost of each pizza is given by the following function:

Where:
r: It's the radius of the pizza
IF a pizza cost $26.32 we have:

We cleared the radius, using
:

We choose the positive value:

So, the radius of the pizza is 
Then, the diameter is: 
Finally, the diameter of the pizza is:
Answer:
Option B