Match the following classes of algae with their characteristic colours:
$A.$ Cyanophyceae $a.$ Green colour
$B.$ Chlorophyceae $b.$ Blue-green colour
$C.$ Phaeophyceae $c.$ Red colour
$D.$ Rhodophyceae $d.$ Brown colour

• A
  $A-a, B-b, C-c, D-d$
• B
  $A-b, B-a, C-d, D-c$
• C
  $A-b, B-a, C-c, D-d$
• D
  $A-d, B-b, C-a, D-b$