Provide an Appropriate Response $f(x, y)=x^{2}+y^{2}$ , the Purpose of Finding the Critical Points Is Which

Multiple Choice

Provide an appropriate response.
-Given $f(x, y) =x^{2}+y^{2}$ , the purpose of finding the critical points is which of the following?
(i) find local minimums, if they exist
(ii) find local maximums, if they exist
(iii) find saddle points, if they exist
(iv) find interior points, if they exist

A) All are correct.
B) (i) , (ii) , and (iii) are all correct.
C) Only (i) and (ii) are correct.
D) Only (iii) is correct.