c) Respiratory rate 10/minThe nurse should report a respiratory rate of less than 12/min to the provider, because this is a manifestation of magnesium toxicity. The nurse should ensure that the antidote, calcium gluconate, is readily available.Oliguria is a manifestation of magnesium toxicity. The nurse should report a urinary output of less than 25 to 30 mL/hr to the provider.Nausea is an expected adverse effect of magnesium sulfate. The nurse should reassure the client and provide comfort measures.Flushing and feeling hot is an expected adverse effect of magnesium sulfate. The nurse should reassure the client and provide comfort measures.