Final answer:
The most likely administrative security control adopted by a company with sensitive information is to prohibit downloading data to USB drives to prevent unauthorized data copying and leaks.
Step-by-step explanation:
The administrative security control most likely to be adopted by a company handling high-level sensitive information is prohibiting downloading data to USB drives. This measure is designed to prevent unauthorized copying and potential leakage of sensitive data. Employers often take this step to safeguard against both internal and external threats to data security. Restricting employee access to official emails may also be relevant, but it doesn't specifically protect against the potential physical transfer of data. The other options are generally less relevant to protecting sensitive information directly.