Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Maintaining the population of Europe with existing food supplies continued to be a problem after the middle of the thirteenth century. B. The delicate balance between population and food supply in Europe was apparent in years of poor harvest half a century before it became a crisis in the fourteenth century. C. Clear signals of the emerging crisis in Europe appeared in the thirteenth century in the form of bad weather, social unrest, and insufficient food. D. In the thirteenth century, a problem emerged in Europe when the food supply was sufficient to feed the population only occasionally.