Find the Real Zeros of the Function, State Their Multiplicities $f ( x ) = x ^ { 2 } + 10 x + 21$

Multiple Choice

Find the real zeros of the function, state their multiplicities if it is a number other than 1.
- $f ( x ) = x ^ { 2 } + 10 x + 21$

A) $x = - \sqrt { 21 } , x = \sqrt { 21 }$
B) $x = - 7 , x = - 3$
C) $x = - 7 , x = 28$
D) $x = 3 , x = 7$