Answer:
The correct answer is - a. Fluorine is the leaving group in Sarin.
Step-by-step explanation:
A leaving group is a group that leaves a complete negative charge in heterolytic cleavage when it separates out from the molecule. Sarine reacts with the active site of the enzyme acetylcholinesterase that is essential for nerve transmission.
In this given case, Sarin that is an acid fluoride and ester of methyl phosphonic acid, the fluorine atom is present is the one that leaves with a complete negative charge, therefore, fluorine is the leaving group in Sarin.
Thus, the first option is correct that Fluorine is the leaving group in Sarin.