Given below are two statements, one is labeled as Assertion A and the other is labeled as Reason R.

Assertion A : The spin only magnetic moment value for ${\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{3-}\text{ is }1.74\mathrm{BM}\text{, whereas for }{\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}\text{ is }5.92$ BM.

Reason  R : In both complexes , Fe is present in +3 oxidation state.
In the light of the above statements, choose the correct answer from the options given below :

Assertion At ${\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{3-}$  CN is a strong field ligand. Therefore pairing occurs first 

$\text{no. of unpaired }{\mathrm{e}}^{-}\mathrm{s}=1$

H₂O is a weak field ligand. Therefore splitting occurs.

$\text{ No of unpaired }{e}^{(-)}S=1$

$\therefore \text{ Magnetic moment }=\sqrt{5\left(7\right)}=5.92\text{ BM. }$

Reason R : In both complexes, Fe is present in +3 oxidation state. But it does not explain assertion.

$\therefore$Both A and R are true but R is not correct explanation of A.