Explanation:

The **Bastar Rebellion of 1910** (also known as Bhumkal Rebellion) was a significant tribal uprising against the British colonial forest policies and the exploitation by local administrators and traders in the Bastar region of present-day Chhattisgarh. The primary cause was the British attempt to reserve two-thirds of the forest, displacing tribals and restricting their traditional forest rights. Due to the intensity and widespread nature of the rebellion, the British authorities were compelled to make concessions. Specifically, **the area to be reserved was reduced to roughly half of that planned before 1910**. This was a major victory for the rebels, demonstrating the power of organized resistance. Therefore, Option D is the true statement. Option A is incorrect; while Gunda Dhur, a Dhurwa tribal from Nethanar, was a key leader, the rebellion involved various tribal communities across Bastar, not just Dhangars from Kanger forest. Option B is incorrect; forest reservation was a broader policy, not starting specifically at Nethanar. Option C is incorrect; Gunda Dhur, despite British efforts, managed to evade capture and became a legendary figure among the tribals, symbolizing their resistance.