From which part of Acacia, the 'kattha' used with betel is obtained?
The correct option is B Heart wood
Heartwood is the central region of old trees, that is formed earlier during growth, with tannins, resin and other substances imparting it the black color. It serves to provide mechanical support. Kattha is obtained by boiling the heartwood of Acacia catechu, which is also known as 'khair tree', in earthen pitchers followed by its cooling and crystallization.