Name the following in the figure shown below the base or bases, the part labeled pq and the figure itself

a circle, radius, sphere
b circle, diameter, cylinder
c none, radius, cylinder
d none, diameter, sphere

Take a look at it.  We know it's a cone, right?  So that answers your 3rd question. The base (or the part that it sits on if you put it down), is a circle.  The other parts it can't sit on without rolling, so it has to be that circular side.  And if that's a circle, that means that any line from the center to the outside 'circumference' is the radius.  This means that the answer is A.