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