The correct option is B Waldsterben effect
Forest die back is the other name for Waldsterben effect. It is a condition in trees or woody plants in which peripheral parts are killed, wither by parasites or due to conditions like acid rain and drought. Two of the nine tipping points for major climate changes, forecast for the next century are directly related to forest die backs. Phomopsis azadirachtae is a fungus of the Phomopsis genus that has been identified as the fungus responsible for die back of Azadirachta indica.