Some malware employs a pakcer to get obfuscated. What does this technique consist of$?$ A$.$ Some parts of the code are encrypted or compressed, but the PE header remains unchanged B$.$ the original PE header and code are placed in a new section, which is made unreadable by encrypting or compressing it C$.$ the malicous code, at runtime, downloads a compressed or encrypted DLL from a C$2$ server, which is then uncompressed or unencrypted and executed D$.$ at some point, the code calls a function to download and execute a malicious payload from a C$2$ server