The production of sufficient acid by fermentation of glucose leads to decrease in pH such that pH of the medium falls below 4.5. Which of the following test can detect it?

The production of sufficient acid by fermentation of glucose leads to

1.	The production of sufficient acid by fermentation of glucose leads to decrease in pH such that pH of the medium falls below 4.5. Which of the following test can detect it?
A.	Methyl red test
B.	Indole test
C.	Voges-Proskauer test
D.	Citrate utilization test
Answer» B. Indole test