The sweat glands and piloerector muscles of hairy skin are innervated by which of the following fiber types?

A、Cholinergicpostganglionicparasympatheticfibers;
B、Cholinergicpostganglionicsympatheticfibers;
C、Adrenergicpreganglionicparasympatheticfibers;
D、Adrenergicpostganglionicsympatheticfibers