Pick out the wrong statement.

• Linear polymers are formed from bifunctional groups only and are normally thermoplastic.
• Cross-linked branched chain polymers are either elastometric or thermosetting.
• Branching in case of cross-linked polymers caused by small amount of impurities in bifunctional monomer formulation reduces its solubility and increases the softening point.
• Dibasic acids reacts with dihydric alcohols to give polyesters using addition polymerisation reaction.