This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sampling, Subject name: Social & Preventive Medicine
In Random sampling, the probability of selecting an item from the population is:- 
Select and explain. 
A. Not Known, B. Known, C. Undecided, D. Zero
B: Known
Answer: B: Known 
Explanation: Probability sampling - Samples selected through probability sampling are also frequently known as random samples . Randomness, however, does not imply that the sample units are selected haphazardly. On the contrary, in this method of sampling, the probabilities for selecting the different samples from a population are specified, and the probabilities for the units of the population to appear in the samples are known.