Hedge funds are stepping up their presence in the options market, suggesting they see further upside to the renminbi's rebound against the dollar. Demand for options to profit from renminbi appreciation is increasing, according to traders. Investors are targeting a rise to 7 or stronger by the end of the year, according to derivatives data from the Singapore Exchange. Behind this bet is confidence that China will continue to provide policy support and a shift in expectations for US interest rate...