Final answer:
A hydropathy plot, which analyzes the hydrophobicity of amino acid sequences, is typically used to identify transmembrane segments of integral proteins. Therefore, the correct option is D.
Step-by-step explanation:
The technique often used to identify transmembrane segments of integral proteins is a hydropathy plot. This plot is used to predict hydrophobic domains and potential membrane proteins by analyzing the amino acid sequence of a protein. Hydrophobic alpha-helical domains are indicative of membrane-spanning proteins, and this can be predicted without even isolating the protein, but by using information on the DNA sequence of a gene encoding the protein. A hydropathy plot can give us insights into the hydrophobicity of the different regions of a protein, which is crucial for determining if a protein is likely to span a membrane.