Choice A reason: Tetracycline HCl can make the skin more sensitive to sunlight and increase the risk of sunburn. Therefore, the client should avoid exposure to direct sunlight and use sunscreen or protective clothing while taking the drug. Choice B reason: Orange juice is acidic and can decrease the absorption of tetracycline HCl in the GI tract. Therefore, the client should not take the drug with orange juice or other acidic beverages. Choice C reason: Serum drug levels are not routinely monitored for tetracycline HCl, as there is no established therapeutic range or toxicity level for this drug. Therefore, the client does not need to return to the clinic weekly to obtain serum drug levels. Choice D reason: Milk and antacids can bind to tetracycline HCl and reduce its effectiveness. Therefore, the client should not take the drug with milk or antacids or within 2 hours of consuming them.