The correct answer is Steghide. It is a steganography program that is able to hide data in various kinds of image- and audio-files. The presence of a tool like Steghide on a suspect's computer might suggest that the individual is using steganography to conceal data. The other options listed are also tools used in penetration testing, but they do not specialize in steganography like Steghide. Gobuster is for enumerating files and directories on web servers, Snow is a tool for hiding text in whitespace, and OWASP ZAP is for finding vulnerabilities in web applications. So although these are related to the fields of cybersecurity and penetration testing, they would not typically be used for detecting steganographic data.