Read the excerpt from the article Skara Brae: The people of Skara Brae then farmed the surrounding lands, with evidence suggesting that they grew barley and other grains. They kept cows and pigs, and they fished in the ocean for a good part of their diet.

As the number of people grew, the village expanded. Covered tunnels and alleyways were built to connect all the homes. This would have protected people traveling from one house to another from cold winter weather. Because of the connections between the houses and the shared workspace, archaeologists believe that Skara Brae was a close-knit community.

Which of the following correctly paraphrases the excerpt?

a
As the close-knit community of Skara Brae grew, the farmers and fishermen built tunnels to connect their homes. This allowed them to visit without venturing out into the cold.

b
Because the community of Skara Brae wanted to be closer, they built tunnels between their houses in order to move their cattle more easily.

c
The cows and pigs that the people of Skara Brae kept helped them build tunnels between houses. They did this because they were a close-knit community.

d
The number of people living in Skara Brae increased because the tunnels they built between houses meant they never had to go outside.