The following complexes are given:
$1$. $\text{trans}-[Co(NH_3)_4Cl_2]^+$
$2$. $\text{cis}-[Co(NH_3)_2(en)_2]^{3+}$
$3$. $\text{trans}-[Co(NH_3)_2(en)_2]^{3+}$
$4$. $[NiCl_4]^{2-}$
$5$. $[TiF_6]^{2-}$
$6$. $[CoF_6]^{3-}$
Choose the correct code:

• A
  $1$,$2$ are optically active,$3$ is optically inactive
• B
  $4$,$5$ are coloured and $6$ is colourless
• C
  $4$ is coloured and $5$,$6$ are colourless
• D
  $2$ is optically active; $1$,$3$ are optically inactive