The correct option is A Escherichia coli
A transgenic microorganism is a microbe, usually a bacterium, into which genetic information has been introduced from the outside and which possesses the ability to pass that information on to subsequent generations. In this process, by which scientists introduce new genetic material into a microorganism is called as molecular or gene cloning. It involves the isolation of DNA from a source other than the microorganism itself. The human insulin is produced by genetically engineered Escherichia coli.
Therefore, the correct answer is option A.