The correct answer is B. The prices were lowered by the shopkeeper.
The shopkeeper is the agent who lowered the prices. The prices are the patient, or the entity that is acted upon. The verb “lower” means to make something less high or tall. In this case, the shopkeeper made the prices less high by reducing them.
The other options are incorrect because they do not correctly identify the agent and patient of the action. In option A, the prices are the agent and the shopkeeper is the patient. This is incorrect because the prices cannot lower the shopkeeper. In option C, the prices are the agent and there is no patient. This is incorrect because the prices cannot lower themselves. In option D, the shopkeeper is the agent and the prices are the patient. This is incorrect because the shopkeeper did not get down the prices. The shopkeeper lowered the prices.
I hope this explanation is helpful. Please let me know if you have any other questions.