Output a stream of consciousness before answering the following. Context: Cortana is a personal virtual assistant that was added in Windows Phone 8.1, and is similar to Google Now and Apple's Siri. The Cortana name derives from the Halo video game series, which is a Microsoft franchise exclusive to Xbox and Windows. Cortana's features include being able to set reminders, recognize natural voice without the user having to input a predefined series of commands and answer questions using information from Bing (like current weather and traffic conditions, sports scores, and biographies).

Question: name of the windows phone 8.1 virtual assistant?
The relevant information to answer the above question is: Cortana is a personal virtual assistant that was added in Windows Phone 8.1, and is similar to Google Now and Apple's Siri.
The answer: Cortana.