**Core Concept**
Type II diabetes with hypertension and mild proteinuria necessitates the selection of an antihypertensive drug that is effective in reducing blood pressure while also protecting the kidneys from further damage. This requires considering the renoprotective effects of various antihypertensive agents.

**Why the Correct Answer is Right**
The patient has diabetic nephropathy, as evidenced by mild proteinuria. The renin-angiotensin-aldosterone system (RAAS) plays a crucial role in the pathogenesis of diabetic nephropathy. Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are particularly effective in reducing proteinuria and slowing the progression of renal disease. They work by blocking the RAAS, thereby reducing the intraglomerular pressure and decreasing the fibrotic process in the kidneys.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because beta-blockers, such as atenolol, are not the first-line treatment for hypertension in patients with diabetic nephropathy. While they can help reduce blood pressure, they do not have the same level of renoprotective effects as ACEIs or ARBs.
* **Option B:** This option is incorrect because calcium channel blockers, such as amlodipine, can increase the risk of hyperglycemia and worsen proteinuria in patients with diabetic nephropathy.
* **Option C:** This option is incorrect because diuretics, such as hydrochlorothiazide, can exacerbate proteinuria and worsen renal function in patients with diabetic nephropathy.

**Clinical Pearl / High-Yield Fact**
In patients with diabetic nephropathy, ACEIs and ARBs should be considered as the first-line treatment for hypertension due to their renoprotective effects. This is in addition to their ability to lower blood pressure and reduce proteinuria.

**Correct Answer: C. Calcium channel blockers are not the first choice for treating the hypertension in this patient.