This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
A patient, Tina was anesthetized with halothane and nitrous oxide and tubocurarine was used for skeletal muscle relaxation. She became hypeensive along with marked muscle rigidity and hypehermia. Lab repos showed that she has developed hyperkalemia and acidosis. This complication was caused by: 
Select and explain. 
A. Block of autonomic ganglia by tubocurarine, B. Pheochromocytoma, C. Activation of brain dopamine receptors by halothane, D. Excessive release of calcium from the sarcoplasmic reticulum
D: Excessive release of calcium from the sarcoplasmic reticulum
Answer: D: Excessive release of calcium from the sarcoplasmic reticulum 
Explanation: (Ref: KDT 6/e p347, 372) The symptoms of the patient (muscle rigidity, hypeension, hypehermia, hyperkalemia and acidosis) suggests the diagnosis of malignant hypehermia. Halothane can precipitate malignant hypehermia is susceptible individuals. SCh increases this incidence. Malignant hypehermia is due to excessive release of Ca2+ from the sarcoplasmic reticulum. Drug of choice for malignant hypehermia is dantrolene that inhibits the release of Ca2+ (by blocking ryanodine receptors in the sarcoplasmic reticulum).