L + M means L is the brother of M.
L - M means L is the son of M.
L ÷ M means L is the wife of M.
L × M means L is the father of M.
then which of the following means R is the mother of T?
1
R ÷ A + S - T
2
R ÷ A × S + T
3
R ÷ A + S × T
4
R ÷ A - S + T