The passage is C: the climax of the poem
The poem's exposition describes who Lochinvar is and where he is coming from. It explains that he is returning to the wedding of his lost love. In the rising action, Lochinvar talks with the bride's father, the bridesmaids swoon, and the bride, herself, is reminded of Lochinvar's charm.
The climax features the two lovers escaping, only to be chased (but not found) by the brides kinsmen.