Given below are two statements labelled as Assertion (A) and Reason (R)

These are the options for the question :Given below are two statements labelled as Assertion (A) and Reason (R)

Assertion : Magnetic moment values of actinides are lesser than the
theoretically predicted values.
Reason : Actinide elements are strongly paramagnetic.
Select the most appropriate answer from the options given below:
a. Both A and R are true and R is the correct explanation of A
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.

The correct answer is -b Both A and R are true but R is not the correct explanation of A.
The magnetic moment is less as the 5f electrons of actinides are less
effectively shielded which results in quenching of orbital contributions , they
are strongly paramagnetic due to presence of unpaired electrons