stock exchanges

Which are the Best stock exchanges to trade Index Options from Australia? Which Indexes offer high liquidity and are better suited from Tax treatment perspective? Has anyone traded in options in Hangseng and Singapore stock markets? How are these markets in terms of liquidity and tax implications?

Hi there, If a company is listed on a stock exchange in its home country at a price of say 1.50 Euro but is listed on NYSE at a price of $20. How does this work? The price varies a lot, so as an investor why would I go to the NYSE price when I can have it for 1.50 Euro? Thanks