IgG antibody can cross placenta and provide natural passive immunity to the developing foetus. Other options are corrected as follows IgA is a dimer found in body secretions such as sweat, tears, saliva, mucus, colostrum, etc. It provide localised protections from pathogens.
IgE is involved in hypersensitive reactions and are present in mast cells and basophil cells.
IgM is found in pentamer form not as dimer.