The points A, B and C have position vectors

\(2\mathbf{j} + 3\mathbf{k}, \quad -5\mathbf{i} + 3\mathbf{j} + \mathbf{k} \quad \text{and} \quad \mathbf{i} + 2\mathbf{j} + 5\mathbf{k}\)

respectively, relative to the origin O.

(a) Find the equation of the plane ABC, giving your answer in the form \(ax + by + cz = d\).

(b) Find the perpendicular distance from O to the plane ABC.

(c) Find the acute angle between the line OA and the plane ABC.