Question

which of the following is the open source operating system
a. Microsoft windows
b. Ubuntu
c. MAC OS x
d. iOs
e. Android

Answer 1

Ubuntu is an open source operating system that could be run on desktop, server, cloud etc (see https://www.ubuntu.com/ for details).

Android is an open source operating system for mobile devices (see https://source.android.com/ for details).

Answer: b) and e).