The centre of mass of from P\\\\(\\begin{array}{l} x=\\dfrac { { { M_{ p } }\\left( { { x_{ p } } } \\right) +{ M_{ q } }\\left( { { x_{ q } } } \\right) +{ M_{ R } }\\left( { { x_{ R } } } \\right) } }{ { { M_{ p } }+{ M_{ q } }+{ M_{ R } } } } \\\\ =\\dfrac { { M\\left( 0 \\right) +M\\left( { PQ } \\right) +M\\left( { PR } \\right) } }{ { M+M+M } } \\\\ =\\dfrac { { M\\left( { PQ+PR } \\right) } }{ { 3M } } \\\\ =\\dfrac { { PQ+PR } }{ 3 } \\end{array}\\\\)Option B.