Although the Heart Does Not Require the Nervous System to Initiate

Multiple Choice

Although the heart does not require the nervous system to initiate contraction events:

A) it is sympathetically innervated via cardiac nerve fibers.
B) it is parasympathetically innervated by vagus nerve fibers.
C) it is innervated by the phrenic nerve.
D) it is innervated by the sympathetic division of the autonomic nervous system only.
E) both (a) and (b) above.