If '×' means 'is father of ', '+' means 'is sister of ', '-' means 'is brother of ', and '÷' means 'is mother of', then which of the following statements means 'S is grand-daughter of P'?
(a) P × T + R ÷ S
(b) P ÷ Q - R ÷ S - T
(c) P × R - T × S
(d) P ÷ Q - R × S + T