Off$-$the$-$shelf software has this benefit...

a$.$

It can be developed in$-$house.

b$.$

It is procured from external developers.

c$.$

It offers significant savings in that the initial cost may be lower because the software. development has been spread over many customers.

d$.$

It can result in a one$-$of$-$a$-$ kind program for a specific application.