It should be option (A)
I. Regression testing ensures that the previously developed and tested software still performs well even after making changes.
II. In the black-box testing, test cases are designed from an examination of the input/output values only and no knowledge of design, or code is required
Equivalence partitioning or equivalence class partitioning is a black box testing technique, where the partitioning is done such that the behavior of the program is similar for every input data belonging to the same equivalence class.