The example that represents a discrete data constraint with viable solutions is "number of tests passed." Discrete data consists of distinct, separate values, and the number of tests passed can only take on whole number values (0, 1, 2, etc.), making it a suitable example of discrete data.
The other examples, like distance between points and average weight of newborns, involve continuous data, while average score on a test typically reflects an average value, which is also continuous.