Explanation
The correct order of evidence from most to least volatile in forensic analysis is based on how quickly the evidence can be lost or altered if not collected or preserved properly. CPU cache is the most volatile type of evidence because it is stored in a small amount of memory on the processor and can be overwritten or erased very quickly. Memory is the next most volatile type of evidence because it is stored in RAM and can be lost when the system is powered off or rebooted. Temporary filesystems are less volatile than memory because they are stored on disk, but they can still be deleted or overwritten by other processes or users. Disk is the least volatile type of evidence because it is stored on permanent storage devices and can be recovered even after deletion or formatting, unless overwritten by new data. References:
https://www.comptia.org/blog/what-is-volatility-in-digital-forensics

Explanation
A cloud access security broker is on-premises or cloud based software that sits between cloud service users and cloud applications, and monitors all activity and enforces security policies A CASB has a separate, and more distinctive role. Differing from the use case for SWG, which focuses on the broader filtering and protection against inbound threats and filtering illegitimate web traffic, a CASB is more deeply integrated and has control over your cloud application usage. It can be tied into an applications API to scan data at rest or can be used with a proxy based deployment to enforce inline policies for more real time protection.