Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $[CoCl(NH_3)_5]^{2+}$ absorbs at a lower wavelength of light with respect to $[Co(NH_3)_5(H_2O)]^{3+}$.
Reason $R$: It is because the wavelength of the light absorbed depends on the oxidation state of the metal ion.
In the light of the above statements,choose the correct answer from the options given below:

• A
  $A$ is false but $R$ is true.
• B
  $A$ is true but $R$ is false.
• C
  Both $A$ and $R$ are true and $R$ is the correct explanation of $A$.
• D
  Both $A$ and $R$ are true and $R$ is $NOT$ the correct explanation of $A$.