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: Social & Preventive Medicine
Feature of slow sand filter 
Select and explain. 
A. Fit in a little space, B. Filter is cleaned by back washing, C. Can be handled by less killed person, D. Used in Big cities
C: Can be handled by less killed person
Answer: C: Can be handled by less killed person 
Explanation: None