Find the Domain and Range and Describe the Level Curves $$f ( x , y ) = e ^ { x + y }$$

Multiple Choice

Find the domain and range and describe the level curves for the function f(x,y) .
- $$f ( x , y ) = e ^ { x + y }$$

A) Domain: all points in the first quadrant of the xy-plane; range: all real numbers; level curves: lines x + y = c
B) Domain: all points in the xy-plane; range: real numbers z > 0; level curves: lines x + y = c
C) Domain: all points in the first quadrant of the xy-plane; range: real numbers z > 0; level curves: lines x + y = c
D) Domain: all points in the xy-plane; range: all real numbers; level curves: lines x + y = c