Former US president Donald Trump on Saturday said that he has decided on a running mate for the US presidential election in November, but has not yet told anyone about it. When asked by a reporter on Saturday in Philadelphia whether he had decided on his pick for vice president, Trump replied: “In my mind, yeah.” Asked if anyone knew his selection, he said, “No, nobody knows.” Trump had travelled to Philadelphia in the state of Pennsylvania for a campaign appearance and beforehand stopped off at a steak restaurant, where he was cheered by supporters and also answered a few questions from repor…