'M ! N' means M is the son of N.
'M @ N' means M is the brother of N.
'M # N' means M is the sister of N.
'M * N' means M is the mother of N.
'M & N' means M is the father of N.
In the expression P @ Q ! R # S & T, how Q is related to T?
1
Father
2
Mother
3
Cousin
4
Sister