[A] It provides a duality between analytic solutions of differential equations and holomorphic functions on compact manifolds.

[B] It establishes an equivalence between the category of flat connections on complex algebraic varieties and the category of local systems, relating systems of differential equations to their monodromy representations.

[C] It is a method in geometry for constructing projective varieties from Kähler manifolds.

[D] It describes a canonical morphism between the fundamental groups of differentiable and algebraic varieties.