Each of these four options is built from three independent components, the seated base, the hand position, and the direction of the bend, so checking each option component by component pinpoints exactly where the wrong ones go wrong.
- Sit in Padmasana, clasp wrists over the head, bend forward and touch the forehead to the floor: The base (Padmasana) is correct and the forward bend to the floor is correct, but the hand position is wrong; clasping the wrists over the head does not create the shoulder-opening lock that Yog Mudra requires before the forward fold.
- Sit in Padmasana, clasp wrists behind the back, bend forward and touch the forehead to the floor: All three components match, the base is Padmasana, the hands are clasped behind the back, and the movement is a forward bend ending with the forehead on the floor, exactly as the pose is defined.
- Sit in Vajrasana, clasp wrists behind the back, bend forward and touch the forehead to the floor: The hand position and the forward-bending movement are both correct, but the base posture is wrong; Yog Mudra is traditionally performed from Padmasana, not Vajrasana, which is a kneeling pose rather than the cross-legged lotus seat.
- Sit in Vajrasana, clasp wrists over the head, bend forward and touch the forehead to the floor: Here, only the forward-bending movement matches; both the base (Vajrasana instead of Padmasana) and the hand position (over the head instead of behind the back) are incorrect, making this the option furthest from the actual pose.
Checking the base, hand position, and direction of movement separately shows that only one option gets all three components right at once.
Therefore, the correct answer is Sit in Padmasana, clasp wrists behind the back, bend forward and touch the forehead to the floor.