Find the Coordinates of the Other Endpoint of the Segment $\left( \frac { \mathrm { p } + \mathrm { b } } { 2 } , \frac { \mathrm { q } - \mathrm { y } } { 2 } \right)$

Find the coordinates of the other endpoint of the segment, given its midpoint and one endpoint.
-midpoint $\left( \frac { \mathrm { p } + \mathrm { b } } { 2 } , \frac { \mathrm { q } - \mathrm { y } } { 2 } \right)$ , endpoint $( \mathrm { p } , \mathrm { q } )$

A) $\left( \frac { 3 p + b } { 4 } , \frac { 3 q - y } { 4 } \right)$
B) $( b , y )$
C) $( b , - y )$
D) $\left( \frac { b } { 2 } , - \frac { y } { 2 } \right)$