To answer this question, you need to understand the concepts of grey-box testing, black-box testing, and white-box testing.
Option A) Grey-box testing - Grey-box testing is a software testing method that combines elements of both black-box testing and white-box testing. In grey-box testing, the tester has limited knowledge of the internal workings of the system being tested. This option is incorrect because scanning underlying source code with a database of regular expressions does not involve limited knowledge of the internal workings of the system.
Option B) Black-box testing - Black-box testing is a software testing method where the tester has no knowledge of the internal workings of the system being tested. The tester only focuses on the inputs and outputs of the system. This option is incorrect because scanning underlying source code with a database of regular expressions requires some knowledge of the internal workings of the system.
Option C) White-box testing - White-box testing is a software testing method where the tester has full knowledge of the internal workings of the system being tested. The tester can access and analyze the source code, data structures, and algorithms of the system. This option is correct because scanning underlying source code with a database of regular expressions requires full knowledge of the internal workings of the system.
Option D) None of these - This option is incorrect because the correct answer is Option C, white-box testing.
The correct answer is C) White-box testing. This option is correct because scanning underlying source code with a database of regular expressions requires full knowledge of the internal workings of the system.