Uh, I think you mean antonym.
Anyways, here are some antonyms.
Careless, Certain, Foolish, Inattentive, Incautious
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.
Answer:
d. It is assumed that the search pool is ordered.
Explanation:
A binary search/logarithimic search/half interval search/binary chop refers to search algorithm in computer science that sorts data in array in key:value arrangements. In order to locate a value in binary search, the key to the value in a sorted array is located. A binary search is characterized by an ascending, descending order arrangement of the array.