**Core Concept**
A solitary thyroid nodule can be either benign or malignant, and its management depends on the results of thyroid function tests, imaging studies, and fine-needle aspiration cytology (FNAC). The presence of a cold nodule on a thyroid scan suggests decreased uptake of radioactive iodine, which can be seen in both benign and malignant nodules.

**Why the Correct Answer is Right**
A cold nodule on a thyroid scan is not diagnostic of malignancy. In fact, most cold nodules are benign and have a low risk of malignancy. The American Thyroid Association recommends that patients with cold nodules undergo FNAC to evaluate the nodule's nature. The presence of a cold nodule on a thyroid scan is merely a radiologic finding that warrants further investigation, not a definitive diagnosis of malignancy.

**Why Each Wrong Option is Incorrect**
**Option B:** FNAC is indeed required in the further management of this patient, as it provides valuable information about the nodule's cytology and helps guide further management.

**Option C:** If the FNAC report is inconclusive, the patient may not necessarily undergo hemithyroidectomy. The management of a solitary thyroid nodule with an inconclusive FNAC report depends on the patient's overall clinical context, the nodule's size and characteristics, and the presence of any suspicious features.

**Option D:** Indirect laryngoscopy is indeed an important step in the preoperative evaluation of patients with thyroid nodules, particularly those with a history of neck irradiation or a family history of thyroid cancer. This procedure helps assess the mobility of the vocal cords and can identify any potential airway complications.

**Clinical Pearl / High-Yield Fact**
In the management of solitary thyroid nodules, it's essential to remember that a cold nodule on a thyroid scan is not diagnostic of malignancy. FNAC is a crucial diagnostic tool that helps evaluate the nodule's cytology and guide further management.

**✓ Correct Answer: A. Cold nodule on thyroid scan is diagnostic of malignancy.**