The IT role responsible for the installation and maintenance of hardware and software that make up a computer network is the Network Administrator. Their responsibilities include:
* Network installation: Setting up and configuring network hardware, such as routers, switches, firewalls, and servers.
* Network maintenance: Ensuring the network operates smoothly, performing regular updates, and troubleshooting issues.
* Security management: Implementing security measures to protect the network from unauthorized access, attacks, and breaches.
* Performance monitoring: Monitoring network performance and making necessary adjustments to optimize speed and reliability.
Therefore, the Network Administrator is the correct role for these responsibilities.
References
* William Stallings, "Data and Computer Communications," Pearson.
* Andrew S. Tanenbaum and David J. Wetherall, "Computer Networks," Pearson.

The operating system (OS) is the primary software that manages all the hardware and other software on a computer. It acts as an intermediary between users and the computer hardware. The OS handles basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating networking, and managing files. Examples include Windows, macOS, and Linux.

* An input device is any hardware component that allows a user to enter data into a computer.
* A scanner is an input device that converts physical documents into digital format.
* The other options:
* Printer is an output device.
* Flash drive is a storage device.
* CD can be both storage and media for input/output depending on the context but is not primarily used for direct data input.
* Therefore, a scanner is the correct answer for an input device.
References:
* "Introduction to Computer Science" by ITL Education Solutions Limited, which discusses input and output devices.
* "Digital Fundamentals" by Thomas L. Floyd, which includes information on various peripherals.

Big data refers to the use of large and complex data sets that traditional data-processing software cannot adequately handle. Businesses leverage big data to analyze and systematically extract information from large datasets, which helps them gain valuable insights, improve decision-making, enhance customer experiences, and optimize business processes. This capability is critical in today's data-driven world, where informed decision-making can significantly impact a company's success.