As a response to overcrowding, residents of medieval cities built taller houses and shops. Option A is correct.
First, medieval cities had small populations relative to cities today, however, cities used to be very small and very crowded. Besides, such cities were dirty places. The 12th and 13th centuries marked a period of economic growth which led to the rebirth of cities.
Most people in Medieval England were village peasants but religious centres attracted people and many developed into towns or cities.
