Shiva, the symbol of yoga, is the god of destruction and creation. For the creation of the new, the destruction of the old is necessary, which may be painful, but without it, nothing new can be created.
In yoga, the yoga pose is only the third of the eight limbs, but it is necessary even in the postures. In forward bending, which is the basis of the pose, most people try to do a pose like A. And I first try to destroy the incorrect upper body shape, and most of them listen to me honestly, but a few stubborn and inflexible mind people cannot abandon their old ways and continue in pose A. As long as you continue to practice in the wrong way, you will not make progress.
The mind and body are closely linked and their flexibility is also related to each other
You will never progress from A to C, as you make bridge the gap between the chest and the thighs, but you can easily progress from B to C if you gradually extend your legs from the state where there is no gap between the chest and the thighs.