This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Health education & planning, Subject name: Social & Preventive Medicine
A systematic observation and recording of activities of one or more individuals at random interval is done in - 
Select and explain. 
A. System analysis, B. Network analysis, C. Work sampling, D. Input-output analysis
B: Network analysis
Answer: B: Network analysis 
Explanation: A network analysis is a graphical plan of all events and activities to be completed inorder to reach an end objective.It brings greater discipline in planning.Two common types of network techniques are PE CPM(refer pgno:872 park 23 rd edition)