Which of the following groups of plants produces economically useful fibers?

• A
  $Gossypium$,$Hibiscus$,$Crotalaria$
• B
  $Gossypium$,$Cassia$,$Lycopersicum$
• C
  $Gossypium$,$Brassica$,$Glycine$
• D
  $Gossypium$,$Agave$,$Nicotiana$