E. The fireplace with a chimney.
Step-by-step explanation:
During the medieval ice age, which lasted from the 14th to the 19th century, temperatures in Europe were significantly cooler than they are today. To combat the cold, people relied on fireplaces to heat their homes. However, early fireplaces were inefficient and often resulted in smoke and soot filling the house. The invention of the chimney in the 12th century allowed smoke to be directed outside, which made fireplaces much more effective and allowed people to heat their homes more efficiently. Glass windows were not commonly used until the 17th century, and electricity was not discovered until the 19th century. Natural gas and oil were not commonly used for heating until the 19th and 20th centuries, respectively.