Creating separate entities for each task type allows the model to better understand the specific information required for each task and extract it accurately. Including specific variations for each task type helps the model recognize and classify the user's messages correctly. Option A would not be effective as it would not allow the model to differentiate between different tasks. Option C is incorrect as using regular expressions alone may not capture all the variations and nuances of user messages. Option D is not a viable approach as not creating any entities would make it difficult for the model to extract relevant information from user messages.