Final answer:
The three major signs of Graves' disease are exophthalmos, goiter, and tachycardia, related to the overproduction of thyroid hormones due to the presence of thyroid-stimulating immunoglobulin.
Step-by-step explanation:
Graves' disease is the most common cause of hyperthyroidism and is known to exhibit several distinctive signs and symptoms. Three major signs of Graves' disease include exophthalmos, goiter, and tachycardia. These symptoms arise due to the production of thyroid-stimulating immunoglobulin (TSI), which can lead to an overactive thyroid. Specifically, exophthalmos, also known as Graves' ophthalmopathy, is characterized by bulging eyes. A goiter is an enlargement of the thyroid gland visible as a swelling in the neck. Finally, tachycardia refers to a rapid and irregular heartbeat that patients with Graves' disease often experience.
Accordingly, the correct answer to the question is option 'b': Exophthalmos, goiter, and tachycardia. Option 'd' is partially correct as it describes symptoms such as heat intolerance, weight loss, and muscle weakness, which are also present in hyperthyroidism but are not as specific or prominent as the three chosen for the correct answer.