TOKYO - Japan's top currency diplomat Masato Kanda said on Wednesday that Japanese authorities won't rule out any options on currencies if speculative moves persist, a comment apparently warning against a sell-off in the yen. It was the strongest warning since mid-August, when the Japanese currency slid past the key threshold of 145 per dollar. Since then, the authorities have stopped firing warning shorts, keeping traders guessing on Japan's intervention strategy. Kanda, vice minister of finance for international affairs, was speaking to reporters after the dollar broke above 147 yen to edge closer to 148 yen overnight, this year's strongest ever against the Japanese currency....Keep on reading: Japan won’t rule out options if FX speculation persists, says Kanda