The style of John Updike's story "The Slump" is not easy to define because of each of the following except A. it is not a poem. B. it is not an essay. C. it lacks plot structure. D. it is not a monologue.

D.

Explanation:

"The Slump" is written by John Updike. It is a self-narrative story of a professional ballplayer. One day he finds himself unable to hit the ball as good as he used to before.

It is a monologue. A monologue "is a speech given by a single character." And in "The Slump" the narrator gives a monologue about his slump to an unidentified audience.