Which of the following operating systems are security concerns in a company's infrastructure as of summer 2023?

Windows 7 is considered a significant security concern in a company's infrastructure as of summer 2023 because Microsoft officially ended support for the operating system in January 2020. Without ongoing security updates and patches, systems running Windows 7 are vulnerable to new threats and exploits that could compromise the integrity, confidentiality, and availability of sensitive data. Organizations still using Windows 7 would be at a higher risk for attacks since any vulnerabilities discovered post-EOS (End of Support) would not be addressed by Microsoft.

The other options present different security considerations but are not as critical. Windows 10, for example, is actively supported by Microsoft, meaning it receives regular security updates and features designed to protect against evolving threats. MacBook Pro 2012, while potentially outdated in hardware terms, may still run more current operating systems that are actively supported. Android 6.0 is an older version of Android, and while it lacks the updates available to newer versions, devices running it may not be prevalent in a corporate environment that typically adapts to newer technologies. Hence, the major concern lies with Windows 7 due to its lack of security support.