To solve this problem, we need to identify which option is not a method of in situ conservation of biodiversity.$\newline$In situ conservation refers to the conservation of species in their natural habitats. Let's analyze each option:$\newline \bullet$Option 1: Biosphere Reserve$\newline$ - Biosphere reserves are areas designated to promote and demonstrate a balanced relationship between humans and the biosphere. They are a method of in situ conservation.$\newline \bullet$Option 2: Wildlife Sanctuary$\newline$ - Wildlife sanctuaries are protected areas that provide habitat for wildlife and are a method of in situ conservation.$\newline \bullet$Option 3: Botanical Garden$\newline$ - Botanical gardens are places where plants are grown for display, education, and conservation. They are ex situ conservation methods, as they involve conserving species outside their natural habitats.$\newline \bullet$Option 4: Sacred Grove$\newline$ - Sacred groves are patches of forest or natural vegetation that are conserved by local communities due to religious or cultural beliefs. They are a method of in situ conservation.$\newline$Based on the analysis, the correct answer is Option 3: Botanical Garden, as it is not a method of in situ conservation.