Roots in some gymnospermic genera have fungal association in the form of $A$ in $B$. Here,$A$ and $B$ refer to:

• A
  $A$-mycorrhiza; $B$-$Pinus$
• B
  $A$-mycorrhiza; $B$-$Cycas$
• C
  $A$-lichen; $B$-$Pinus$
• D
  $A$-lichen; $B$-$Cycas$