Sebastian is accustomed to using his desktop computer to share and update his latest information and ideas with friends through different social media. Last Friday when he entered the web address in the browser's address bar, the browser displayed "This site can't be reached" (as shown in Figure 1). He was quite sure that the web address was correctly entered, and did not know why he is getting such an error. He then called his neighbour Monica to ask if she could access that social media site using a browser. Monica replied him that no problem at all. She then used a Windows command prompt to find the IP address of that social media web server and enquired Sebastian to key in the IP address in his browser. Sebastian took her advice and was finally able to successfully access the web site login page. www.facebook.com C https://www.facebook.com This site can't be reached www.facebook.com's DNS address could not be found. Diagnosing the problem. Try running Windows Network Diagnostics DNS PROBI STARTED Reload Figure 1 (a) Determine the main reason for Sebastian's encountered problem. Give him a detailed explanation. (b) Distinguish whether the social media (as shown in Figure 1) is shareware or freeware. Elaborate on your answer. Although Monica and Sebastian live on the same estate, they use two different broadband Internet connection services at home. Monica's Internet Service Provider (ISP) uses cable television lines and cable modems, while Sebastian's ISP uses a local telephone network and ADSL modems. (c) Name the specific physical transmission medium that Monica and Sebastian use for their broadband modems, respectively. In addition to being a broadband modem cable, give ONE example of a common use of these TWO physical transmission media separately. (d) Both Monica and Sebastian set up a hotspot for sharing the Internet connection to their smartphones and mobile devices in their homes. Describe ONE communication device that Monica and Sebastian can use to set up a hotspot. Specify TWO wireless transmission media that a smartphone may use. (e) Name the full forms of MAN, PAN, WAN, and WLAN, then rank them according to their geographic coverage from largest to smallest.