The best black-box test technique to test the processing functionality of this system is equivalence partitioning enhanced with boundary value analysis. Equivalence partitioning is a technique that divides the input domain into subdomains that are expected to behave similarly. Boundary value analysis is a technique that tests the values at or near the boundaries of an input domain. These techniques are suitable for testing a system that depends on defined ranges of input variables, as they can ensure that all subdomains and boundary values are covered by test cases. Verified References: [ISTQB® Certified Tester Advanced Level Test Analyst CTAL-TA], Section 3.2.1, page 33 and Section 3.2.2, page 35.