Algae include unicellular forms like $A$,filamentous forms like $B$,and colonial forms like $C$. Here $A, B$,and $C$ refer to:

• A
  $A-Chlamydomonas, B-Volvox, C-Ulothrix$
• B
  $A-Ulothrix, B-Volvox, C-Chlamydomonas$
• C
  $A-Volvox, B-Ulothrix, C-Chlamydomonas$
• D
  $A-Chlamydomonas, B-Ulothrix, C-Volvox$