Mumbai, Feb. 3 -- The Indian rupee plunged 55 paise to close at an all-time low of 87.17 (provisional) against the US dollar on Monday. Rupee fell past a crucial mark as dollar pushed higher after Trump announcement on imposing tariff over neighboring countries and China and as internstional oil prices spiked above 74 per barrel. The dollar index soared to three week high on Monday morning after US President Donald Trump set tariffs over the weekend. On Saturday, Trump finally signed off on threatened 25-percent tariffs on neighboring Mexico and Canada -- despite sharing a free trade pact -- and hit China with a 10-percent tariff in addition to already enacted levies. The dollar index is quoting at 109.26, up 1% on the day. Rupee also era...