C. SHA-3 (Secure Hash Algorithm 3).
Explanation: SHA-3 is a cryptographic hashing algorithm that generates a fixed-size hash value (checksum) for a given file. This hash value is unique to the file's content. By comparing the SHA-3 hash of the executable file in question to a known-good hash value or to other hashes from similar files, the investigator can determine if the file has been tampered with or if it matches a known executable from the same source.
The other tools and methods mentioned (ldd, bcrypt, ssdeep, and dcfldd) are not typically used for identifying the creator or tampering of executable files:
ldd is used to display the shared libraries required by an executable but doesn't help with identifying the creator.
bcrypt is a cryptographic hashing function used for securely hashing passwords, not for identifying the creator of files.
ssdeep is a tool for fuzzy hashing, used to compare similar files for similarities, but it doesn't identify the creator of files.
dcfldd is a variant of the dd command used for creating and verifying forensic images, which is useful for preserving evidence integrity but not for identifying the creator of files.