In Which of the following types of white box testing are the test cases designed based on data flow within the code?

Data flow testing focuses on the lifecycle of variables within code - specifically the points where a variable is defined (assigned), used in a computation, and undefined or killed. Test cases are designed to cover paths between these definition and use points, helping detect defects such as use-before-initialization or variables used after being freed. It is a structural white box technique that targets data-related anomalies rather than purely structural paths.

Control flow testing designs test cases based on the logical flow of control (decisions and conditions) through the program, not based on how data values move.

Path testing aims to execute every distinct path through a program's control flow graph, focusing on execution routes rather than variable data lifecycles.

Branch testing ensures every decision branch (true/false outcome) in the code is exercised at least once, which is a subset of control flow testing and unrelated to data variable tracking.