Explanation:

A disc, such as a CD, DVD, or Blu-ray, is physically inserted into a disk drive (also known as an optical drive) within a computer system for the purpose of reading or writing data. Option (a) 'In a modem' is incorrect because a modem is a networking device used for internet connectivity, not for disc insertion. Option (b) 'In the hard drive' is incorrect as a hard drive is an internal, sealed storage unit for persistent data, and discs are not inserted into it. Option (c) 'Into the CPU' is fundamentally incorrect; the CPU (Central Processing Unit) is the computer's 'brain' and processes instructions, it has no mechanism for disc insertion. Therefore, the correct location for inserting a disc is into a disk drive, making option (d) the accurate choice. Option (e) 'None of these' is incorrect as a correct option has been identified.