Final answer:
The recommended monitoring method for an individual with potential high I-131 intake is a thyroid count, as it specifically measures the radioactivity in the thyroid gland where I-131 concentrates.
Step-by-step explanation:
For an individual likely to receive more than 10% of an Annual Limit on Intake (ALI) for I-131, the recommended type of individual monitoring is D. thyroid count. I-131 concentrates in the thyroid gland, hence thyroid monitoring would provide the most accurate assessment of the intake of this particular radionuclide. Air sampling could measure general radioactive contamination but is not specific to personal exposure. Extremity and whole body dosimeters are more suitable for external radiation exposure monitoring and may not be as effective at measuring intake of I-131. Thyroid count involves measuring the radioactivity emitted from the thyroid, providing a targeted and sensitive detection of I-131 intake.