Mural joints are develop in

Mural joints are vertical joints that commonly develop in massive igneous rocks, especially in granite bodies.

They are formed due to contraction and release of stresses during the cooling and solidification of the granite mass.

These joints are called mural joints because they appear like the walls of a structure, often intersecting at right angles.

Option A: Basalt usually develops columnar joints, not mural joints.

Option C: Sandstone may show bedding and fracture joints but not mural joints.

Option D: None is incorrect because mural joints specifically occur in granite.

Therefore, mural joints are typically developed in granite.