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: Microbiology
Which one of the following is TRUE regarding media for culturing organisms? 
Select and explain. 
A. Agar has nutrient propeies, B. Chocolate medium is selective medium, C. Addition of selective substances in a solid medium is called enrichment media, D. Nutrient broth is basal medium
D: Nutrient broth is basal medium
Answer: D: Nutrient broth is basal medium 
Explanation: Nutrient broth is an example for simple medium or basal medium. It consists of peptone, meat extract, sodium chloride and water. Agar is used for preparing for solid media. Its chief constituent is a long chain polysaccharide. It has viually no nutritive value and is not affected by the growth of bacteria. Chocolate agar, blood agar, and egg media are examples for enriched media. They are used to grow bacteria which are more exacting in their nutritional needs. Addition of substances which have a stimulating effect on the bacteria to be grown or an inhibitory effect on those to be suppressed in a liquid medium is called enrichment media. The result is an absolute increase in the numbers of the wanted bacterium. Ref: Ananthanarayan and Paniker's Textbook of Microbiology By Ananthanarayan And Paniker, 7th edition, Page 34, 37.