In Matthew the mother of the sons of Zebedee asks; in Mark, James and John ask. Which was it?

Here is how each Gospel tells it. Matthew: "Then the mother of the sons of Zebedee came to him with her sons, kneeling and asking a certain thing of him" (20:20); Jesus says to her, "What do you want?", and she asks, "Command that these, my two sons, may sit, one on your right hand and one on your left hand, in your Kingdom" (20:21). Jesus answers, "You don’t know what you are asking" (20:22), and in the Greek the verbs behind know and asking there are both plural. "They said to him, “We are able.”" (20:22), and the ten are indignant "with the two brothers" (20:24). Mark: "James and John, the sons of Zebedee, came near to him, saying, “Teacher, we want you to do for us whatever we will ask.”" (Mark 10:35), and "They said to him, “Grant to us that we may sit, one at your right hand and one at your left hand, in your glory.”" (Mark 10:37). Each Gospel tells it in its own words. These notes set the two side by side, don't put them together into one telling, don't say which is more exact, and say nothing of the mother beyond what Matthew says.