Option 1 -> Polio is prevented by a separate vaccine (OPV/IPV), not included in DPT.
Option 2 -> Pertussis (whooping cough) is the "P" in DPT vaccine.
Option 3 -> Diphtheria is the "D" in DPT vaccine.
Option 4 -> Tetanus is the "T" in DPT vaccine.
Hence, Option 1: Polio -> The DPT vaccine specifically protects against Diphtheria, Pertussis, and Tetanus. Polio requires a separate vaccination (OPV or IPV) and is not part of the DPT triple vaccine formulation -> correct