Alice wrote a program with four main modules. Each major module containing four submodules. Each major module includes a function call to every other major module, while each of the submodules within a major submodule includes a function call to the other submodules contained within that module. Which of the following structures best describes Alice's second design? a$)$hierarchy b$)$layering $.$ c$)$modularity d$)$client $-$server $.$ e$)$memory