The example that represents a discrete data constraint with viable solutions is "number of tests passed."
Discrete data typically involve countable values, such as whole numbers (e.g., 0, 1, 2, etc.), and the "number of tests passed" is a countable quantity. In contrast, the other options (average score, average weight, and distance) involve continuous data, which can take on a range of values and are not countable in the same way.