The answer is C.
In Chapter XVIII, after Dimmesdale meets Hester in the forest where she encourages him to return to England with her, he becomes exuberant at the thought of escaping with Hester. However, even then, there are omens that point to the failure of this plan. For one thing, Dimmesdale worries that Pearl may not accept him as her father, a worry that is fostered by his observation that Pearl is slow to approach her parents as she refuses to cross the brook and come to them.
Nevertheless, Dimmesdale returns home hopefully; he excitedly hurries along the path in the forest. In such a state, the minister has strange impulses; for instance, he can hardly resist acting out of character and uttering some blasphemy to an old deacon he sees coming along the path. His elation is only superficial because, Hawthorne writes,
the breach which guilt has once made into the human soul is never, in this mortal state, repaired....But there is still the ruined wall, and, near it, the stealthy tread of the foe that would win over again his unforgotten triumph.
Thus it is that in Chapter XXIII as the temporarily elated Dimmesdale writes his Election Day Sermon, he arrives at a different state of mind from what may be expected by the reader. When Governor Bellingham approaches Dimmesdale with an anxious eye, he is alarmed to see "something in the latter's expression that warned back the magistrate." Then, the minister calls Hester and Pearl onto the scaffold where he confesses his sin before the townspeople in a scene that recalls the first scaffold scene. Rushing forward, the avenger Chillingworth urges the minister to repulse Hester and the child, telling him, "I can yet save you! Would you bring infamy on your profession?" But, when the minister repels him by saying, "With God's help I shall escape thee now!" Chillingworth concedes,
"Hadst thou sought the whole earth over...there was no one place so secret,--no high place nor lowly place, where thou coulst have escaped me,--save on this very scaffold.
Therefore, both Dimmesdale and Chillingworth realize that the platform of confession of sin is the only escape, underpinning Hawthorne's theme of "Be true! Be true!" which is stated in the concluding chapter.