|A) Closed source software||B) Open source software|
|C) Horizontal market software||D) vertical market software|
Microsoft Office is an example of a Horizontal market software.
In computers, software is a collection of programs which performs a task. Horizontal market software is an application software that is useful in a wide range of industries. Horizontal market software is also known as "productivity software."
Email, Payroll, Operating Systems (OS), Spread sheets, etc...