A patient is brought to the casualty in the state of altered sensorium.He was on Lithium treatment for affective disorder and has suffered through an attact of epileptic fits. On examination he has tremors, increased DTR's and incontinence of urine.He has also undergone an episode of sever gastroenteritis 2 days ago.The serum Lithium was found to be 1.95 meq/Lit.The probable cause for his present state is -

• A. Lithium toxicity
• B. Dehydration
• C. Depressive Stupor
• D. Manic episode