Donald Trump has just issued a $5 million challenge to Barack Obama -- if POTUS releases his college records, Trump says he'll donate $5 mil to a charity of B.O.'s choice.

Trump just made the "announcement" via a YouTube video -- saying, "If Barack Obama opens up and gives his college records and applications ... and if he gives his passport applications and records I will give to a charity of his choice -- Inner City Children of Chicago, American Cancer Society, AIDS Research ... a check immediately for 5 million dollars."

Trump continued, "The check will be given within one hour after he releases all of the records ... he'll be doing a great service for the country if he does this."

"If he releases these records, it will end the question and indeed the anger of many Americans ... they'll know something about their president ... their President will become transparent ... like other Presidents."