Consider the following statements and choose the incorrect option:
$a$. Large and more numerous nucleoli are present in cells actively carrying out protein synthesis.
$b$. Nuclear pores allow bidirectional movement of molecules.
$c$. Cytoskeleton is a glycolipid structure for mechanical support,motility and maintenance of the shape of the cell.
$d$. Steroidal hormones are synthesized by Golgi complex.

• A
  $a$ and $b$
• B
  $b$ and $c$
• C
  $c$ and $d$
• D
  $a$ and $d$