Final answer:
Complement receptors 3 and 4 (CR-3 and CR-4) can recognize C3b, a complement component, and LPS, found in the outer membrane of Gram-negative bacteria, but they do not directly recognize nucleic acids.
Step-by-step explanation:
The recognition capabilities of CR-3 and CR-4, referring to complement receptors 3 and 4, include being able to recognize several ligands. Specifically, these receptors are known for their function in the immune system, where they can bind to the complement component C3b as part of the opsonization process. Additionally, these receptors can interact with Lipopolysaccharides (LPS), which are components of the outer membrane of Gram-negative bacteria. However, complement receptors do not directly recognize nucleic acids; instead, other components of the immune system specialize in the recognition of nucleic acids.
Therefore, the correct answer to which ligands CR-3 and CR-4 can recognize from the given options is C3b and LPS, which corresponds to option 'e'. This understanding is central when studying the immune response and inter-cell signaling within the context of immunology.