Correct Answer : March 20, 2013
Explanation :
Docker debuted to the public in Santa Clara at PyCon in 2013. It was released as open-source in March 2013. At the time, it used LXC as its default execution environment.
One year later, with the release of version 0.9, Docker replaced LXC with its own component, libcontainer, which was written in the Go programming language.
In 2017, Docker created the Moby project for open research and development.
