Isn't it obvious that if you are ordering from the US amazon, it will be Region A - that site was meant to serve America, therefore will usually not sell a Region B or C Bluray - if it does, it always have this "Imported" on the title line (you can check Amazon.co.uk to see those items, as you will find a fair bit of imported US BRs).
In any case, Singapore is also under Region A, so why do you need to know if it is Region B or C in Amazon.com?
If you are that curious, you can always check the web for information such as these. Amazon or any other selling sites will only state their own region code and does not tell you if it is region free as far as I know.
I think if you want to have full HD + 7.1/5.1 audio, you can't watch online.
Even if you download mkv file, the size ranging from 10GB to 15GB, but not sure if you can get 5.1 DTS HD Master audio :dunno:
Disclaimer: I am not promoting this site. I also do not know of its legitimacy. So whoever wants to use it , it is at your own risk. Unlilke the high profile anime downloads, you are not downloading. However, you do cache the movies unknowingly. I do not know of the legal implication of watching movies online. Maybe someone who is familiar can advise. Anyway, I have friends from all over the world watching from sites like these. I do not think I am the first to know about this. Anyway, I will remove the wordings so as not to appear as promoting the site.