Final answer:
The lines from "Macbeth" express a deep sense of grief, depicting the sorrow within the kingdom and align with the theme of regret.
Step-by-step explanation:
In Shakespeare's play "Macbeth," the emotions conveyed in the lines "...That it us befitted/To bear our hearts in grief and our whole kingdom/To be contracted in one brow of woe..." clearly express a deep sense of grief. These lines reflect the sorrowful atmosphere following a significant and tragic event in the play. The appropriate emotional response from the given options is (a) regret. The mention of bearing hearts in grief and a kingdom in a state of woe implies a profound regret that is shared among the characters. This sentiment ties in with the overarching themes of loss and mourning that are prevalent in much of the play.