Final answer:
Logbook records for CV and opium sales must be kept for two years according to DEA regulations to prevent substance misuse and ensure compliance with the Controlled Substances Act.
Step-by-step explanation:
The question pertains to the retention period of logbook records for controlled substances. According to the United States Drug Enforcement Administration (DEA) regulations, pharmacies and other entities that deal with controlled substances are required to maintain purchase and sales records, including logbooks for Schedule V controlled substances (CV) and those containing opium, for a period of two years. This requirement is designed to prevent the misuse or diversion of these substances and to ensure compliance with the Controlled Substances Act.