This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: The iPod is a line of portable media players and multi-purpose pocket computers designed and marketed by Apple Inc. The first line was released on October 23, 2001, about 8 months after iTunes (Macintosh version) was released. The most recent iPod redesigns were announced on July 15, 2015. There are three current versions of the iPod: the ultra-compact iPod Shuffle, the compact iPod Nano and the touchscreen iPod Touch. Question: How many different types of iPod are currently available?
three