$.$ Some firms offer $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_,$ which are meant to provide support for very common transactions like order$-$processing and billing, and these things are web$-$based too.

a$.$ application service providers $($ASP$)$

b$.$ Internet business services $($IBS$)$

c$.$ outsource hosting providers $($OHP$)$

d$.$ fixed outsourcing services $($FOS$)$