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: Anatomy
A hypeensive patient Sattu already receiving a drug 'X' to control his BP was prescribed a tricyclic antidepressant. This resulted in the abolition of the antihypeensive action of 'X'. Which of the following drug can be 'X'? 
Select and explain. 
A. Enalapril, B. Clonidine, C. Atenolol, D. Diltiazem
B: Clonidine
Answer: B: Clonidine 
Explanation: (Ref: KDT 6/e p444) TCAs abolish the antihypeensive effect of guanethidine and Clonidine by inhibiting their transpo into the adrenergic neurons.