Answer:
d. does not exist
Step-by-step explanation:
The given limits are;
,
and 
We want to find

By the properties of limits, we have;

This gives us;

Division by zero is not possible. Therefore the limit does not exist.
The answer is 3. I don't know if you want ne to explain or show my work just reply to me.
If the diameter is 10.5 then the radius is 5.25.
This is because the radius of a diameter is half the diameter.
So
10.5/2
= 5.25
Therefore the radius is 5.25