Mycorrhiza is a mutualistic association. How do the organisms involved in this association gain from each other?

• A
  Fungi provide nitrogen to plants,while plants provide shelter.
• B
  Fungi provide water and minerals to plants,while plants provide carbohydrates to fungi.
• C
  Plants provide oxygen to fungi,while fungi provide carbon dioxide to plants.
• D
  Both organisms compete for the same nutrients in the soil.