How allosteric regulation can change an enzyme activity

Which statement most accurately explains how allosteric regulation can change an enzyme’s activity?

a. In allosteric deactivation a regulatory molecule binds to a site other than the active site, resulting in a change in enzyme shape that allows the active site to bind substrate.

b. In allosteric activation a regulatory molecule binds to the active site, allowing substrate binding.

c.In allosteric activation a regulatory molecule binds to a site other than the active site, resulting in a change in enzyme shape that allows the active site to bind substrate.

d.In allosteric deactivation a regulatory molecule binds to the active site, blocking substrate binding.