Which option describes Spero file analysis?
A. a method of analyzing the SHA-256 hash of a file to determine whether a file is malicious or not
B. a method of analyzing the entire contents of a file to determine whether it is malicious or not
C. a method of analyzing certain file characteristics, such as metadata and header information, to determine whether a file is malicious or not
D. a method of analyzing a file by executing it in a sandbox environment and observing its behaviors to determine if it is malicious or not
