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
All are true about levamisole EXCEPT : 
Select and explain. 
A. Act as an immunostimulator, B. Act as an immunodepressor in high doses, C. Single dose is sufficient for the treatment of psoriasis, D. Acts as antihelminthic by causing depolarization
C: Single dose is sufficient for the treatment of psoriasis
Answer: C: Single dose is sufficient for the treatment of psoriasis 
Explanation: Levamisole is an immunomodulator acting as immunostimulant at low doses and immunodepressant at high doses.
It was used as anti-helminthic and causes depolarization by stimulating nicotinic receptors.
It is used for the treatment of colorectal carcinoma in combination with 5-FU.
It is slow to act in psoriasis and requires two-day therapy per week for prolonged periods.