Statements : 1. All chairs laugh.
2. Some birds Laugh.
conclusion -
1. All Chairs are birds - false.
2. Some birds are chairs - false.
3. Those who do not laugh are not chairs- true.( because all chairs laugh. )
4. Some birds do not laugh - false. ( if some birds laught, it doesn't mean that some do not laugh, because some birds laugh may also mean all birds laugh.
ans- only 3.