Explain the difference between Buna $-N$ and Buna $-S$.

• A
  Buna $-N$ is a homopolymer,while Buna $-S$ is a copolymer.
• B
  Buna $-N$ is a copolymer of $1,3-$butadiene and acrylonitrile,while Buna $-S$ is a copolymer of $1,3-$butadiene and styrene.
• C
  Buna $-N$ is a natural rubber,while Buna $-S$ is a synthetic rubber.
• D
  Buna $-N$ is used for making tyres,while Buna $-S$ is used for making oil seals.