Match the regulatory input with its effect on the heart.
| Column I | Column II |
|---|---|
| (a) Sympathetic neural signals | (i) Decrease the rate of heart beat |
| (b) Parasympathetic neural signals | (ii) Increase the rate of heart beat and strength of contraction |
| (c) Adrenal medullary hormones | (iii) Can increase cardiac output |
| (d) Vagus nerve | (iv) A primary parasympathetic nerve to the heart |