Anticodon to DNA sequence conversion for Val Steps:

• Identify the substituted amino acid as Val, with given anticodons CAA, CAG, CAU.
• Recognize that DNA triplets use T instead of U in RNA sequences.
• Match the anticodons: CAA and CAG have no U, so remain CAA/CAG; CAU requires U→T change to CAT.
• Select CAT as the DNA equivalent from the choices, corresponding to the CAU anticodon for Val.

Why D is correct:

• CAT is the direct DNA analog of the RNA anticodon CAU (U replaced by T), per standard nucleic acid sequence conventions.

Why the others are wrong:

• A. GTT does not match any anticodon sequence (CAA, CAG, or CAU) with U→T adjustment.
• B. GAC mismatches all listed anticodons for Val.
• C. CTC mismatches all listed anticodons for Val.

Final answer: D