In context of software testing match of Column-I and Column-II is: Column-I…

Software testing can be classified along two independent axes: the test LEVEL (unit, integration, system, acceptance) describes the scope being exercised, while the test TECHNIQUE (black-box, which derives test cases purely from specified input-output behaviour, vs white-box, which derives them from the internal code structure) describes how test cases are designed. These two axes are independent of each other — per the ISTQB Foundation Level syllabus, black-box, white-box, and experience-based techniques can in principle be applied at any test level, not just one.

1. Alpha Testing, a pre-release trial run by users at the developer's site, is a level-linked practice tied specifically to Acceptance Testing.

2. Usability Testing, which evaluates how easily an end user can operate a product's interface, is most naturally assessed once a complete, integrated system exists to try out; this exam's official key pairs it with System Testing on that basis — though, unlike Alpha Testing's tight link to Acceptance Testing, usability checks are not confined only to the system level as a general software-testing rule.

3. Data Flow Testing, which traces a variable's definition-and-use along execution paths, is a technique label rather than a level-specific practice; this paper's official key applies it to Integration Testing.

4. Black Box Testing, which validates purely from input-output behaviour without inspecting internal code, is the other technique label; this paper's official key applies it to Unit Testing. This is valid precisely because technique and level are independent axes: a unit-level test written purely from a function's specified behaviour, without reading its internal logic, is legitimately a black-box test at the unit level, even though white-box testing is the more common default choice for units.

This pairing matches the officially published final answer key for this HTET 2022 Computer Science paper (Set A, question 150). It is also consistent with the ISTQB Certified Tester Foundation Level syllabus, which explicitly separates test levels from test techniques and states that a technique is not restricted to a single level — addressing the common assumption that Unit Testing must always be White Box testing.

Putting these together gives i-c, ii-d, iii-a, iv-b.