Gold bugs' only problem on Monday was trying to find which of a myriad of bullish factors to pick to explain yet another move to fresh 25-year highs. The usual suspects -- inflation, geopolitical tensions, and a weak dollar -- were all present at the open of trading after a three-day weekend. Most visibly, crude oil topped $70 a barrel amid heightened concerns about Iran's nuclear ambitions. In recent action, crude was gaining 68 cents to trade at $70 a barrel. Gold for June delivery was recently up $13 at $613.80 an ounce, off an earlier 25-year high at $614.30....