Which of the following tools is used for vulnerability scanning and calls Hydra to launch a dictionary attack?

Whisker is a CGI script vulnerability scanner focused on enumerating web server scripts and does not integrate with Hydra for dictionary attacks.

Nmap is a network port and service discovery tool, not a vulnerability scanner that launches dictionary attacks via Hydra.

Nessus, developed by Tenable, is a comprehensive vulnerability scanner that can call external tools such as Hydra to perform dictionary attacks against network authentication services it identifies during a scan. This integration extends Nessus beyond passive checks into active credential testing, making it uniquely match the description in the question.

SARA (Security Auditor's Research Assistant) is a network vulnerability assessment tool but lacks built-in functionality to invoke Hydra for dictionary attacks.