Reward is calculated on:

The correct answer is Amount released to Government exchequer. Informer rewards are typically calculated on the net amount that ultimately benefits the government, such as fines collected, proceeds from seized goods, or recovered funds, after all legal processes and deductions. This ensures the reward is based on the actual financial gain to the state, reflecting the true impact of the informer's contribution. Options A (Total stock seized), B (Value of fine imposed), and D (Auction amount only) are incorrect. These options represent intermediate or partial values; the reward is usually based on the final, realized amount that enters the government treasury.