Locate and Classify All Critical Points for the Given Function $f(x, y)=x^{3}-3 x y+y^{3}+5$

Multiple Choice

Locate and classify all critical points for the given function.
- $f(x, y) =x^{3}-3 x y+y^{3}+5$
Determine only the number of critical points.

A) 3
B) 2
C) 4
D) None of the above is correct.