The correct answer is choice B. The client’s urine output is at least 30 mL/hr. This indicates that the therapy is effective because magnesium sulfate can cause renal impairment and fluid retention, which can worsen the condition of preeclampsia.

A normal urine output is a sign that the kidneys are functioning well and that the fluid balance is maintained.

Choice A is wrong because the client’s blood pressure may not normalize even with magnesium sulfate therapy.

Magnesium sulfate is mainly used to prevent seizures, not to lower blood pressure. Other antihypertensive medications may be needed to control blood pressure in severe preeclampsia.

Choice C is wrong because the client’s deep tendon reflexes are expected to decrease with magnesium sulfate therapy, as it is a central nervous system depressant.

A normal reflex response is 2+, but a lower response (1+ or 0) may indicate magnesium toxicity, which can cause respiratory depression, cardiac arrest, and coma.

Choice D is wrong because the client’s respiratory rate should be monitored closely with magnesium sulfate therapy, as it can also cause respiratory depression.

A normal respiratory rate is 12 to 20 breaths per minute, but a lower rate (less than 12) may indicate magnesium toxicity, which requires immediate treatment with calcium gluconate.