We have a container of ten coloured discs. Five of the discs are red, three are blue and two are green. We randomly select four discs from the box with replacement. Let A be the event that the first selected disc is the only red disc in our four selections. Which of the following events is mutually exclusive of the event A? same number of blue and green discs are selected. third selected disc is the only green disc. second disc selected is blue. same number of red and blue discs are selected. no green discs are selected