The correct answer is C. Decreased bladder capacity.

This is because benign prostatic hyperplasia (BPH) is a condition in which the prostate gland enlarges and compresses the urethra, the tube that carries urine out of the bladder. This can cause difficulty in emptying the bladder completely, leading to increased frequency and urgency of urination, especially at night. The bladder may also lose its elasticity and ability to hold urine as it becomes overstretched.

Choice A is wrong because BPH causes increased urinary frequency, not decreased. This is due to the reduced bladder capacity and the residual urine that remains in the bladder after urination.

Choice B is wrong because BPH does not affect urine concentration directly. However, some medications used to treat BPH, such as diuretics, may increase urine concentration by removing excess fluid from the body.

Choice D is wrong because BPH does not cause increased kidney size. However, untreated BPH can lead to complications such as urinary tract infections, bladder stones, and kidney damage due to backflow of urine or obstruction of urine flow.

Some additional information:.

• BPH is a common condition that affects about half of men over 50 and up to 90% of men over 80.

• BPH is not the same as prostate cancer, but it can have similar symptoms. Therefore, it is important to have regular check-ups and screenings to rule out cancer.

• BPH can be diagnosed by a physical exam, a rectal exam, a urine test, a blood test for prostate-specific antigen (PSA), and other tests such as ultrasound, cystoscopy, or urodynamic testing.

• BPH can be treated by medications, surgery, or other procedures depending on the severity of symptoms, the size of the prostate, and the presence of complications or other health conditions.

• BPH can be prevented or managed by maintaining a healthy lifestyle, such as exercising regularly, drinking enough fluids, avoiding caffeine and alcohol, and eating a balanced diet rich in fruits, vegetables, and protein.