Assertion: If the inner solenoid is much shorter than (and placed well inside) the outer solenoid, then the flux linkage `N_1phi_1` can still be calculated.
Reason: The inner solenoid is effectively immersed in a uniform magnetic field due to the outer solenoid.
Options:
(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 and R is also false.