**Core Concept**
Hypertensive emergencies are medical emergencies that require immediate attention, typically defined as systolic blood pressure (SBP) ≥180 mmHg or diastolic blood pressure (DBP) ≥120 mmHg. However, in this question, the patient has a DBP of 100 mmHg on two consecutive occasions, which is considered hypertension but not an emergency. The treatment should focus on reducing blood pressure to a safe level while minimizing cardiovascular risks.

**Why the Correct Answer is Right**
The correct answer is lifestyle modification with pharmacological treatment. The first step in managing hypertension is lifestyle modification, including dietary changes, increased physical activity, weight loss, and reduced sodium intake. In this case, the patient's DBP is 100 mmHg, which is considered stage 2 hypertension. Pharmacological treatment is necessary to reduce blood pressure to a safe level. The choice of antihypertensive medication depends on various factors, including the patient's medical history, age, and comorbidities.

**Why Each Wrong Option is Incorrect**

**Option A:**
This option is incorrect because antihypertensive medication alone is not sufficient without lifestyle modification. Additionally, starting with a single agent like a beta-blocker may not be the best option for this patient.

**Option B:**
This option is incorrect because immediate hospitalization is not necessary for this patient with a DBP of 100 mmHg on two consecutive occasions. However, close monitoring and follow-up are essential.

**Option C:**
This option is incorrect because amlodipine is a calcium channel blocker, which may not be the first-line treatment for this patient. Additionally, starting with a high dose may increase the risk of side effects.

**Option D:**
This option is incorrect because hydrochlorothiazide is a diuretic, which may be used in combination with other antihypertensive medications but not as the sole treatment for this patient.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the choice of antihypertensive medication depends on the patient's underlying medical conditions, such as kidney disease, heart failure, or diabetes. The American Heart Association (AHA) recommends starting with a combination of medications, including a diuretic, an ACE inhibitor or ARB, and a calcium channel blocker.

**Correct Answer: C. Amlodipine 10 mg once daily.**