Which of the following inequalities always holds? ( ) A. $a ^ { 2 } + b ^ { 2 } \leq 2 a b$ B. $a ^ { 2 } + b ^ { 2 } \geq - 2 a b$ C. $a + b \geq - 2 \sqrt { | a b | }$ D. $a + b \leq 2 \sqrt { | a b | }$
Which of the following inequalities always holds? ( )
A. $a ^ { 2 } + b ^ { 2 } \leq 2 a b$
B. $a ^ { 2 } + b ^ { 2 } \geq - 2 a b$
C. $a + b \geq - 2 \sqrt { | a b | }$
D. $a + b \leq 2 \sqrt { | a b | }$