Causes for urinary retention include which of the following?

Urinary retention can occur due to various physical obstructions or issues affecting the bladder or urinary tract. Bladder stones are indeed a common cause of urinary retention because they can obstruct the flow of urine from the bladder. When stones form in the bladder, they can create a blockage, leading to difficulty in urination and the accumulation of urine, which results in retention.

Other conditions, although related to overall health, do not directly contribute to physical blockage or impairment in the urination process. For example, leukemia is a type of cancer that affects blood cells and does not directly cause urinary retention. Glaucoma primarily impacts the eyes and visual function but does not contribute to urinary issues. Nerve damage can affect bladder control, but the question specifically seeks physical causes of urinary obstruction, making bladder stones the most relevant answer here. Therefore, identifying bladder stones as a cause directly aligns with the mechanics of urinary retention.