Final answer:
Cargo proteins can exhibit both nuclear and mitochondrial signals, as these sequences direct the proteins to their correct organelle destinations within the cell.
Step-by-step explanation:
Proteins destined for specific destinations within the cell exhibit different types of signal peptides which direct them to their target organelles. In the context of the question asked, cargo proteins can indeed have more than one type of signal. For proteins bound to the nucleus, they usually have nuclear localization signals rich in positively charged amino acids that enable binding to nuclear transport receptors. Mitochondrial proteins also bear specific signaling sequences, often an N-terminal signal peptide, that facilitates their recognition by receptor proteins at the outer mitochondrial membrane.Based on this information, the type of signals that cargo can exhibit is (C) Nuclear and mitochondrial signals. These signals are essential for the correct targeting of proteins to their respective organelles, enabling proper cellular function.