Son of Banquo In Macbeth

In Macbeth, the son of Banquo clue in Sunday Times GK Jumbo No 054 23 April 2017

Banquo
The brave, noble general whose children, according to the witches’ prophecy, will inherit the Scottish throne. Like Macbeth, Banquo thinks ambitious thoughts, but he does not translate those thoughts into action. In a sense, Banquo’s character stands as a rebuke to Macbeth, since he represents the path Macbeth chose not to take: a path in which ambition need not lead to betrayal and murder. Appropriately, then, it is Banquo’s ghost and not Duncan’s that haunts Macbeth. In addition to embodying Macbeth’s guilt for killing Banquo, the ghost also reminds Macbeth that he did not emulate Banquo’s reaction to the witches’ prophecy.

Fleance
Banquo’s son, who survives Macbeth’s attempt to murder him. At the end of the play, Fleance’s whereabouts are unknown. Presumably, he may come to rule Scotland, fulfilling the witches’ prophecy that Banquo’s sons will sit on the Scottish throne.

So the answer is Fleance