Why is the total quota less than the total system storage?

View the exhibit.

Why is the total quota less than the total system storage?
A . 3.6% of the system storage is already being used.
B . Some space is reserved for system use, such as storage of compression files, upload files, and temporary report files
C . The oftpd process has not archived the logs yet
D . The logfiled process is just estimating the total quota

Answer: B

Explanation:

https://docs.fortinet.com/document/fortianalyzer/6.2.5/administration-guide/368682/disk-space-allocation