SAT English Practice Question

The following passage is from a short story: "The moon was a pearl in the sky, a perfect circle, and the air was thick with the scent of honeysuckle. The only sound was the gentle chirping of crickets, a sound that seemed to lull the world into a state of peaceful slumber. But the silence was deceptive, for under its tranquil surface, a tension simmered." What is the primary function of the third sentence in the passage?

1. A.introduce a contrast between the tranquility of the scene and the underlying tension.
2. B.describe the speaker's emotional state as they observe the night.
3. C.provide a vivid sensory image of the setting.
4. D.explain the cause of the tension that exists beneath the surface.