Solve the Equation for the Specified Variable $A = \frac { h ( a + b ) } { 2 } \quad$

Solve the equation for the specified variable.
- $A = \frac { h ( a + b ) } { 2 } \quad$ for $a$

A) $a = \frac { A - h b } { 2 h }$
B) $\mathrm { a } = \frac { 2 \mathrm {~A} - \mathrm { hb } } { \mathrm { h } }$
C) $\mathrm { a } = \frac { h b - 2 \mathrm {~A} } { \mathrm {~h} }$
D) $a = \frac { 2 \mathrm { Ab } - \mathrm { h } } { \mathrm { h } }$