The correct response is:
A The angrier the speaker gets, the more he nurses his wrath in secret.
In the poem, the speaker expresses his anger toward his foe by choosing not to communicate his feelings, which causes his wrath to grow. In contrast, when he is angry with his friend, he expresses his feelings, which helps to resolve his anger. This intersection of secrecy and growing wrath is central to the poem's message about the destructive nature of uncommunicated anger.