\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
A bag contains 5 red (R) and 7 blue (B) marbles. One marble is drawn and not replaced, and then a second marble is drawn.
Let \(R_1\) be the event of drawing a red marble first, and let \(B_1\) be the event of drawing a blue marble first.
Let \(R_2\) be the event of drawing a red marble second, and let \(B_2\) be the event of drawing a blue marble second.
Choose the correct probability tree diagram: