Mud cracks are common in which type of sedimentary rocks?

fine-grained sedimentary rocks

Explanation:

Sedimentary or, as it used to be called, sedimentary, rocks are those rocks that are formed in the process of sedimentation or sedimentation. The process of sedimentation, ie the formation of sedimentary rocks, takes place in the general case in four phases, with some of them being absent.

Mud cracks are irregular cracks of an exposed sedimentary layer.