Assertion: Fe(CN)63- ion shows magnetic moment corresponding to two unpaired electrons.

Reason: Because it has d2sp3 type hybridization.

1.  Both assertion and reason are true and the reason is the correct explanation of assertion.

2.  Both assertion and reason are true and the reason is not the correct explanation of assertion.

3.  Assertion is true but the reason is false.

4.  Assertion is false but the reason is true.

Hint: CN is a strong field ligand

According to VBT, the orbital diagram of Fe3+ in Fe(CN)63- is 

Hybridization = d2sp3

 n=1

Hence, the correct assertion is Fe(CN)63-ion shows magnetic moment corresponding to one unpaired electron. 

i.e.,        μ=n(n+2)                   =1(1+2)                 =3=1.73 BM

Hence, the Assertion is false but the reason is true.