Sunil,
Is this for an interview?
None of the questions are good questions. Question 1 is probably the easiest to give a solid answer for.
Question 1. Main thing is to make sure that you keep the connection string correct - you don't want to migrate a universe up to prod and have it still pointing at UAT when you put it live.
Question 2 depends what they mean. Do they have company standards that they expect you to follow? Are you meant to wait for a change request to be assigned to you? Is there more than one person working on the universe? At what stage is the data source - if it is development, how fixed is the schema - will it change? If it's production, when is the change going into production. You then have a deadline when you must deliver on.
Question 3 - very much depends on the report. Simplest answer is to bring back the least possible amount of data to produce the correct report or bring back a larger volume of data far quicker and take the hit on report generation time. This will vary depending on PC v server power.
Question 4 - again, vague. Is it from a purchasing point of view or for a particular report? The answer could be anything from skillset of the current staff to functionality required in the report to timeframe in which the report must be built to data source access
Question 5 just makes no sense. Is it asking about the difference between Live Office and QAAS? From what point of view?
Again, if it's for an interview, just being able to answer questions isn't the same as knowing how to use the tools.