Option B is correct because cursory reconnaissance implies a limited understanding of the environment, which is characteristic of unknown-environment testing. This approach involves gathering only readily available information without detailed knowledge of the target, which is consistent with the scenario of an unknown environment. Option A is incorrect because comprehensive documentation review suggests a familiarity with the environment, making it more suited for known-environment testing. Option C is incorrect because it refers to a practice more commonly associated with known-environment testing where previous engagement information is leveraged to understand the scope. Option D is incorrect as intensive source code analysis indicates deep familiarity with the application, aligning more with known-environment testing.