What are the complications of Scheuermann's disease?

I- Compression of the spinal cord at the apex of the kyphosis.
II- Disc herniation at the apex of the kyphosis.
III- Medullary extradural cysts.
IV- Neuromuscular scoliosis.
a) I and II are correct.
b) I, II, and III are correct.
c) I, II, III, and IV are correct.
d) Only IV is correct.