Which object could be used as monuments of permanent nature to define and mark corners when its diameter exceeds 1 meter?

• A. Immovable or fixed hard rocks or boulders
• B. Concrete post
• C. Living edible fruit tree
• D. Clumps of bamboo

Answer: (A)

In surveying, corners are marked with monuments that will endure over time. When the requirement is a natural feature of permanent nature, a large, immovable rock or boulder serves as the most reliable landmark. A rock or boulder with a diameter greater than about 1 meter is unlikely to shift, be removed, or be distorted by weather, so it provides a stable, long-lasting reference for corner definitions.

Concrete posts, while durable, are artificial landmarks and can be moved or damaged; living trees or bamboo are not dependable long-term markers because they grow, die, or are affected by environmental changes and human activity. Therefore, the best fit for a permanent natural monument is immovable or fixed hard rocks or boulders.