Read the following statements.
$a. 2, 4-D$ is widely used to kill dicotyledonous weeds and does not affect mature monocot plants.
$b.$ Auxin helps to overcome apical dominance.
$c.$ The pigments of euglenoids are identical to those present in higher plants.
$d.$ The cell wall is absent in dinoflagellates.
Select the correct statements -

• A
  $a \& b$
• B
  $b \& c$
• C
  $a \& c$
• D
  $b \& d$