Select all the layers in the cloud services stack in the follows:

Question $1$ options:

Infrastructure$-$as$-$a$-$Service $($IaaS$)$

Software$-$as$-$a$-$Service $($SaaS$)$

Business Process$-$as$-$a$-$Service $($BPaaS$)$

Platform$-$as$-$a$-$Service $($PaaS$)$