PLS HURRY

Which of the following sentences is an example of formal style?

A.
Quantum mechanics provides a math description of things and energy and how they act and influence the world as we know it.
B.
Quantum mechanics, aka quantum physics, developed from quantum theory and dealt with questions, etc., that came out of normal physics.
C.
Quantum mechanics—quantum physics to you and me—uses mathematical descriptions to explain how physical things act like particles or waves.
D.
Quantum mechanics developed in the early 20th century to explain the interactions and behaviors of energy and matter at the molecular, atomic, and subatomic levels.