To answer this question, you need to understand computer abbreviations.
Option A) Order of Significance - This option is incorrect because in the context of computers, the abbreviation 'OS' does not refer to the order of significance.
Option B) Open Software - This option is incorrect because although 'OS' can be associated with open-source software, it is not the most common or widely known abbreviation for open software.
Option C) Operating System - This option is correct. In the context of computers, 'OS' typically refers to the abbreviation for "Operating System." An operating system is a software that manages computer hardware and software resources and provides common services for computer programs.
Option D) Optical Sensor - This option is incorrect because 'OS' is not a commonly used abbreviation for optical sensor.
The correct answer is C) Operating System. This option is correct because 'OS' typically stands for Operating System in the context of computers.