Answer:
Option: B. Tombs
Explanation:
The most common form of megalith architecture in Europe during the Neolithic era was a tomb. Megalith tombs are scattered across landscapes from Germany to Portugal. These tombs are considered to be the oldest architecture in northeast Europe, built between 5000 BC and 2000 BC. Tombs were different in design in various regions, some round and long mounds, built for the people who died during that era.