Let Then F Is

A)Continuous at (2,1,1)
B)Discontinuous at \left

Multiple Choice

Let $f ( x , y , z ) = \left\{ \begin{array} { c l } \frac { x - y - z } { x ^ { 2 } - ( y + z ) ^ { 2 } } & x ^ { 2 } \neq ( y + z ) ^ { 2 } \\\frac { 1 } { 4 } & x ^ { 2 } = ( y + z ) ^ { 2 }\end{array} \right.$ . Then f is

A) Continuous at (2,1,1)
B) Discontinuous at (2,1,1) because f is undefined at(2,1,1)
C) Discontinuous at (2,1,1) because the limit of f at (2,1,1) does not exist
D) Discontinuous at (2,1,1) because the limit of f at (2,1,1) is different from the function values at (2,1,1)
E) Discontinuous at (2,1,1) for a reason that is different from the ones above