The cause of cell differentiation is that different cells:

Cell differentiation occurs when cells become specialized in structure and function. This process is primarily influenced by the expression of different genes rather than the genetic code itself. While all cells in an organism contain the same DNA, it is the selective expression of certain genes that leads to the development of various cell types, such as nerve cells, muscle cells, and blood cells.

The correct choice highlights that cells express alternate genetic information, which means that even though they share a common DNA sequence, they activate different sets of genes to produce proteins necessary for their specific roles within the body. This selective gene expression is what allows for the vast diversity of cell types and functions necessary for the organism's development and maintenance.

In the context of the other options, encoding different DNA would imply significant genetic differences between cells, which is not the case in a multicellular organism where all cells possess the same genetic blueprint. Having different chromosomes is also not accurate, as all somatic cells share the same number and type of chromosomes. Lastly, containing similar protein information would suggest that the cells produce the same proteins, which contradicts the idea of differentiation—each specialized cell type has distinct proteins that enable its specific functions.