Answer:
Barroreceptors are specific type of receptors that are present within the membrane or wells of the blood vessels and monitor the changes occur in blood pressure.
The major and important barroreceptors are located in carotid sinus and the aorta for detecting fluctuation in the blood pressure. If blood pressure falls these receptors firing rate decreases and barroceptors reflexes act to increase heart rate in order to restore blood pressure in an individual.
Thus, the correct answer would be - increasing heart rate.