This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
A patient ingested some unknown substance and presented with myoclonic jerks, seizures, tachycardia and hypotension. ECG shows a heart rate of 120/min. The arterial blood revealed a pH of 7.25, pCO2 of 30 mm Hg and bicarbonate ions are 15 mmol/L. The most likely  poisonous agent is: 
Select and explain. 
A. Amanita phalloides, B. Ethylene glycol, C. Imipramine, D. Phencyclidine
C: Imipramine
Answer: C: Imipramine 
Explanation: None