To determine which two locations are most probable for locating the cloud of electrons, we would typically need more context about the locations (A, B, C, D) and the characteristics of the electron cloud.
In the context of atomic and molecular structure, the electron cloud is usually found in regions where the probability density of finding electrons is high, often described by electron orbitals.
If you provide more details about what locations A, B, C, and D represent, I can help you analyze which pair might be most probable for locating the cloud of electrons.