Which set of test inputs provides the highest level of boundary coverage using two-point BVA?

Boundary Value Analysis (BVA) is a testing technique that focuses on the values at and around the boundaries of input ranges. When applying two-point BVA, testers aim to ensure coverage of the boundary values as well as values just below and above those boundaries.

In the context of the provided choices, option C includes test inputs that effectively represent boundary values around a critical threshold: 20°C. It includes values just below and above that boundary, specifically 19°C and 22°C, which are essential for assessing how the system behaves at and around this threshold. Moreover, it also includes a value like 10°C, which may be the lower boundary based on the context of input expectations.

This choice is designed to identify any issues that could arise at the edges of the defined input range involving the boundary of 20°C. It strategically examines conditions immediately preceding and following the target boundary, which is a core principle of BVA.

The other choices do not demonstrate the same thorough approach in examining boundary conditions. While they may include several relevant values, they do not consistently focus on the specific boundaries that matter most for determining how the application handles values at those critical thresholds. Therefore, option C stands out for its development of a set of inputs that maxim