The correct answer is: A. Google Reader
Google Reader was an RSS feed aggregator and web-based newsreader developed by Google. It allowed users to read and manage feeds from websites, blogs, and other online sources. Google Reader was discontinued on July 1, 2013.
B. Yahoo Mail is a free email service provided by Yahoo!. It is one of the most popular email services in the world, with over 250 million active users. Yahoo Mail offers a variety of features, including a large storage capacity, spam protection, and the ability to send and receive emails from any device.
C. EmailRackspace is a web-based email service provided by Rackspace. It offers a variety of features, including a large storage capacity, spam protection, and the ability to send and receive emails from any device. EmailRackspace is a paid service, but it offers a free trial.
D. All of the mentioned is not the correct answer because Google Reader is a discontinued service.