The disconnected lines drawn on a map for showing the slope are called (B) Hachure. Hachures are short, parallel lines that are drawn on a map to represent relief features such as slopes and hills. The spacing and orientation of hachures provide a visual indication of the steepness and direction of slopes on the map. Hachures are commonly used in cartography to enhance the representation of terrain and elevation.

Mahatma Gandhi was first arrested during the 'Satyagraha' in the year 1908. He was arrested in South Africa during the protest against the discriminatory laws imposed on the Indian community, known as the "Asiatic Registration Act" or the "Black Act."