Answer: A) Modular decomposition
Explanation: Modular decomposition is the composition of a graphs into small modules. These modules are the subset of the whole graphs and thus the part of the graph. These modules are these very design efficient and so they are not capable of handling the exceptions .They have precise representation which has modules which cannot seem to have exception because that will disturb the structure of the graph .
Operating System (OS) is the answer.
An application runs in/on an OS. It is not the OS itself. Like Word or Chrome are applications.
Systems is too generic and not specific enough to mean anything in this context. Throw away answer.
Network Operating System does not 'usually' run on a hard drive but on memory chips in things like routers, wireless access points and switches that move network traffic.
