Every crystal system does not have all the four types of unit cells (simples, face centered, end centered and body centered). But orthorhombic crystal class has all four types of unit cells - primitive, face-centered, body-centered and end-centered.

Crystal Class for which all the four types of unit cells are possible: Orthorhombic

Explanation:
A crystal lattice is an array of points representing the positions of the atoms, ions, or molecules in a crystal. The unit cell is the smallest repeating unit of a crystal lattice. There are seven crystal systems, each of which has a unique combination of symmetry elements. Each crystal system is further divided into several crystal classes based on the presence or absence of additional symmetry elements.

The four types of unit cells are:

1. Primitive cubic (P): In this type of unit cell, the lattice points are located only at the corners of the unit cell. The unit cell has a single lattice point, and the lattice points are not shared by any other unit cell.

2. Body-centered cubic (BCC): In this type of unit cell, the lattice points are located at the corners and in the center of the unit cell. The unit cell has two lattice points, and the lattice points are shared by eight neighboring unit cells.

3. Face-centered cubic (FCC): In this type of unit cell, the lattice points are located at the corners and in the center of each face of the unit cell. The unit cell has four lattice points, and the lattice points are shared by two neighboring unit cells.

4. Base-centered cubic (BC): In this type of unit cell, the lattice points are located at the corners and on the faces of the unit cell. The unit cell has two lattice points, and the lattice points are shared by four neighboring unit cells.

Orthorhombic crystal system:
The orthorhombic crystal system has three axes of different lengths, all of which are perpendicular to each other. It has no center of symmetry or any other symmetry element except for the three mutually perpendicular twofold axes. The orthorhombic crystal system has two lattice parameters (a and b) that are equal, and a third lattice parameter (c) that is different.

All the four types of unit cells are possible in the orthorhombic crystal system. Therefore, the correct answer is option D (Orthorhombic).