In a certain code language,
A + B means 'A is the mother of B'.
A - B means 'A is the brother of B'.
A × B means 'A is the wife of B'.
A ÷ B means 'A is the father of B'.
Based on the above, how is P related to S if 'P × Q ÷ R - T × S'?
1
Father-in-law
2
Mother-in-law
3
Sister
4
Brother