You are given a sentence from a conversation between a human and a virtual assistant. Your task is to classify the sentence into one of the following five action categories - INFORM, INFORM_INTENT, OFFER, REQUEST, REQUEST_ALTS. If the sentence is about informing something, generate 'INFORM'. If it is about requesting something, generate 'REQUEST'. If the sentence mentions requesting an alternative option than the one provided, generate 'REQUEST_ALTS'. Similarly, generate 'OFFER' if the sentence is offering some information. If the sentence is about showing intent to do something, generate 'INFORM_INTENT'.

Example Input: Sounds great. Where is it? When does it start?
Example Output: REQUEST

Example Input: There is an event. It's Mets Vs Dodgers taking place at Citi Field.
Example Output: OFFER

Example Input: What type of concert is it?
Example Output:
REQUEST