A user arrives at a railway station that she has never visited before, carrying a Personal Digital Assistant (PDA) that is capable of wireless networking. (a) Describe the required information by the user about the local services and amenities at that station, without key in the station's name or attributes. (7 marks) (b) What are technical challenges that must be overcome the faced issues? (8 marks) (c) What are the advantages and disadvantages of Hypertext Markup Language (HTML), Uniform Resource Locator (URLs) and Hypertext Transfer Protocol (HTTP) as core technologies for information browsing? Are any of these technologies suitable as a basis for client-server computing in general? (10 marks)