Find a Polynomial of Least Degree with Only Real Coefficients $3 + \sqrt { 6 } , 3 - \sqrt { 6 }$

Multiple Choice

Find a polynomial of least degree with only real coefficients and having the given zeros.
- $3 + \sqrt { 6 } , 3 - \sqrt { 6 }$ , and 3

A) $f ( x ) = x ^ { 3 } - 9 x ^ { 2 } + 21 x - 9$
B) $f ( x ) = x ^ { 3 } - 11 x ^ { 2 } + 21 x + 9$
C) $f ( x ) = x ^ { 3 } + 9 x ^ { 2 } + 21 x - 9$
D) $f ( x ) = x ^ { 3 } - 11 x ^ { 2 } + 21 x + 11$