Transmission Media

Correct Answer: Shielded twisted pair

Shielded twisted pair cable should be used in an office environment that has multiple sources of electromagnetic interference. This type of cable has a protective shield around the wires, which helps to insulate the data signals from the EMI, providing better speed and performance without fear of interference. The other options would not be as effective. Unshielded twisted pair doesn't have this protective shield, and thus is more susceptible to interference. Multimode fiber, though it can effectively avoid EMI, is more expensive and could be an overkill for a typical office environment. Coaxial cable can handle EMI but is less common in office environments due to higher cost and complexity in installation compared to twisted pair cabling.

Correct Answer: Wireless

The most suitable type of network transmission media for the small business described is 'Wireless'. The reason is that a wireless network can be deployed quickly and is a cost-effective solution as it doesn't require physical cabling installation, reducing hardware and labor costs. Moreover, there are no limitations on where devices can be located (as long as they are within range of the wireless access point), and it isn't susceptible to cabling interferences. In contrast: 'Unshielded twisted pair', 'Shielded twisted pair', and 'Multimode fiber' are types of wired networks, which would require time and expense for cable installation and management, they are also prone to signal interference and have limitations concerning the layout of network devices.

Correct Answer: Single-mode fiber

The best suited transmission media for this scenario is Single-mode fiber. This is because Single-mode fiber offers the best performance for long distances. It utilizes a single light path through the fiber enabling it to travel longer distances without losing the signal quality. The other options, Multimode fiber, Shielded twisted pair, and Unshielded twisted pair, are not the best for this scenario. Multimode fiber is best suited for short distances as it uses multiple light paths which can cause signal degradation over long distances. Shielded twisted pair and Unshielded twisted pair are used for shorter distances and might not be able to cover the 1 km distance effortlessly, besides they are prone to electromagnetic interference.