Final answer:
Correct option is 3 Feedback inhibition is an example of enzyme regulation through allosteric control, where the end product of a metabolic pathway inhibits an enzyme involved in its own production.
Step-by-step explanation:
An example of an enzyme being allosterically regulated is feedback inhibition. This type of regulation involves end products of a metabolic pathway acting as allosteric inhibitors. For instance, in the biosynthesis of isoleucine, threonine deaminase is allosterically inhibited by isoleucine, which ensures that the production of isoleucine is shut down when its levels are sufficient for the cell's needs.
In contrast to competitive inhibition and cooperativity, which involve substances binding to the active site, feedback inhibition involves the binding of an inhibitor to an allosteric site, causing a conformational change that affects the active site indirectly. Allosteric control can also include non-competitive inhibitors that bind to an enzyme at an allosteric site but are not necessarily end products of a metabolic pathway like in feedback inhibition.