The mutual inductance of a pair of solenoids depends on

their separation as well as their relative orientation

The correct answer is Option (1) → their separation as well as their relative orientation

Correct statement:

☀ their separation as well as their relative orientation

Explanation: Mutual inductance depends on the geometry of the solenoids, their relative orientation, and the distance between them. It does not depend on the material of the wires or the currents themselves.