Complete the sentence: The doctors tried everything they could to ............ the patient's blood pressure.

Explanation

'Produce' means to cause (a particular result or situation) to happen or exist. 'Reduce' means to make smaller or less in amount, degree, or size. 'Clarify' means to make (a statement or situation) less confused and more comprehensible. 'Hasten' means to be quick to do something. 'Reduce' is used in association to decrease something that is high (like blood pressure) hence is best fitted for this context.