Final answer:
For a patient with benign prostatic hyperplasia, the most relevant assessment would be the distention of the lower abdomen due to the incomplete emptying of the bladder.
Step-by-step explanation:
The most relevant assessment for a patient admitted to the hospital with benign prostatic hyperplasia (BPH) would be distention of the lower abdomen. BPH can cause constriction of the urethra as it passes through the middle of the prostate gland, leading to a number of lower urinary tract symptoms, which include a sensation that the bladder is not emptying completely. This incomplete emptying can cause a distended bladder, which presents as distention of the lower abdomen.