Step 1: Understanding the Concept:
Controlled substances, such as narcotics (opioids) and psychotropic drugs, have a high potential for abuse and diversion. Strict legal and administrative controls are required for their storage.
Step 2: Detailed Explanation:
1. Double-Lock System: To prevent unauthorized access or theft, these drugs must be stored in a secure, immovable metal cabinet or safe. The "double-lock" requirement means two different locks must be opened, often requiring two different keys held by two different authorized personnel (like a pharmacist and a nurse supervisor).
2. Inventory: Every single dose must be accounted for in a dedicated register.
3. Others: Open shelves (Option A) or general storage (Option B) are illegal under the NDPS Act. Refrigeration (Option D) is only required if the specific drug is thermolabile, not as a general security rule.
Step 3: Final Answer:
The double-lock system is the mandatory security standard to prevent the diversion of controlled substances in a hospital setting.