which of these is a memory in LangChain? select anyone 1. Converstation TokenBufferMemory. 2. ConversationBuffetMemory. 3. ConversationSummaryMemory. 4. All of the listed options

The correct option is **1. ConversationTokenBufferMemory**. As of my last knowledge update in October 2023, this is a recognized memory type in LangChain. The other options listed do not correspond to standard memory types in LangChain as known at that time.