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: Medicine
All are TRUE about pneumococci, EXCEPT: 
Select and explain. 
A. Spherical gram positive bacteria, B. 22 species are recognised, C. They reduce iron in hemoglobin to produce a green colour in blood agar, D. They grow best in 40% CO2
D: They grow best in 40% CO2
Answer: D: They grow best in 40% CO2 
Explanation: Pneumococci are spherical gram-positive bacteria . Greek streptos, meaning "twisted," and kokkos, meaning "berry." 22 streptococcal species are recognized and are divided fuher into groups based on their hemolytic propeies. S. pneumoniae belongs to the alpha-hemolytic group that produces a greenish color on blood agar because of the reduction of iron in hemoglobin The bacteria are fastidious and grow best in 5% CO2. Ref: Harisson, Edition - 18, Page 1151