Answer
Refer answer below.
Work Step by Step
a. Domain : A set of all $(x,y)$ when $(x,y)\ne 0$
b. Range: Real numbers.
c. The level curves are the circles whose center is at origin (0,0) with radius $r \gt 0$
d. Boundary point lies at the origin (0,0) refers to a single point.
e. Open
f. Unbounded
