The correct answer is A) the rising action.
The part of the plot that immediately follows the exposition or set up is called the rising action.
When we are referring to a plot in a story, the rising action is the relevant parts of the story or incidents that generate suspense in the audience. It also creates interest in the story or generates emotions such as tension for what is about to happen. In the narrative of the story, the rising action takes the audience through turns of events in order to get to the climax of the plot. So yes, the part of the plot that immediately follows the exposition or set up is called the rising action.