As far as I know, in a lattice every element should have at-least one least upper bound and one greatest lower bound.
In figure 2) Every element has LUB and GLB, even b and c have GLB d.
In figure 3) Even here every element has LUB and GLB.
So both should be lattice according to me.But the answer is none of them are lattice.
So, should LUB and GLB of a particular pair of elements be unique ? I have not seen unique word anywhere in the definition of a lattice. Also, why is (ii) figure not a lattice ?