Given below are four jumbled sentences select the option that gives their correct logical sequence.

A. Some moulds produce toxins.
B. Some are harmful and cause infections or produce toxins, e.g., clostridium botulism and salmonella.
C. Micro-organisms are present everywhere and some are useful in making curd, cheese and bread.
D. Aspergillus flavus produces aflatoxin in groundnuts, cereals and spices.