Regarding shoulder dystocia, which is correct?

Regarding shoulder dystocia, which is correct?

a) It is not associated with maternal diabetes mellitus
b) Arrest of labour occurs at pelvic inlet
c) Increased possibility if epidual anaelgesia is given
d) Most cases can be resolved by hyper flexing the thighs onto the abdomen.
e) Erb’s palsy (C8-T1) is a complication