**Explanation:**

A castle is a large building with high, thick walls and towers that was built in the past to protect against attack. Let's break down the options and explain why the correct answer is option 'C' (castle):

a) **Church:** A church is a religious building used for Christian worship. It typically has a spire or a dome, but it does not have high, thick walls and towers for protection against attacks. Therefore, a church is not the correct option for a large building with these characteristics.

b) **Cathedral:** A cathedral is a large Christian church that is the principal church of a diocese, where the bishop's seat is located. Cathedrals can be grand and elaborate, but they are not specifically designed for protection against attacks. Like churches, cathedrals do not have high, thick walls and towers. Therefore, a cathedral is not the correct option for a large building with these characteristics.

c) **Castle:** A castle, as described in the question, is a large building with high, thick walls and towers that was built in the past to protect against attacks. Castles were often fortified structures, serving as both residences for nobles and defensive fortifications. They were designed with defensive features such as battlements, moats, and drawbridges. Therefore, a castle is the correct option for a large building with these characteristics.

d) **Cottage:** A cottage is a small, cozy house, typically located in a rural or semi-rural area. It is not a large building with high, thick walls and towers for protection against attacks. Therefore, a cottage is not the correct option for a large building with these characteristics.

In conclusion, the correct option that describes a large building with high, thick walls and towers built in the past to protect against attacks is a castle (option 'C').