The scenario points directly to information gathering from the robots.txt file. A robots.txt file is typically located at the root of a website (e.g., https://example.com/robots.txt) and is intended to instruct search engine crawlers which paths should or should not be indexed. During web reconnaissance, testers often review robots.txt because it can unintentionally disclose sensitive directories, administrative panels, staging paths, backup locations, or restricted areas that the organization hoped would remain obscure. The scenario explicitly says Sofia found “a crawler directive at the server’s root” that “allows unintended indexing of restricted areas,” and that this “reveals internal paths.” That is exactly the kind of leakage that can come from misconfigured or overly revealing crawler directives.

This is considered an early-stage reconnaissance / information gathering technique because it does not require exploitation. It leverages publicly accessible configuration hints to map the application’s hidden structure. Even when robots.txt is used correctly, the listed disallowed entries can still serve as a roadmap of interesting targets; if configured incorrectly (for example, allowing indexing or exposing sensitive paths), it can increase exposure by helping those paths surface in search results or be discovered faster by attackers.

Why the other options are less accurate:

Vulnerability Scanning (A) implies using scanners to identify known flaws; here, the tester is manually/strategically inspecting a crawler directive for exposed paths.

Web Server Footprinting/Banner Grabbing (C) focuses on identifying server type/version and technologies via headers or responses, not discovering hidden paths from crawler directives.

Directory Brute Forcing (D) uses wordlists to guess directories; Sofia’s discovery comes from a disclosed list of paths, not brute-force guessing.

Therefore, the technique is B. Information Gathering from robots.txt File.