The requirement specifies that a bonus should be paid if the total amount of sales (TAS) made during the year is 300,000€ or more. The software incorrectly implements this requirement with "IF (TAS = 300,000)" instead of "IF (TAS >= 300,000)". Using boundary value analysis (BVA), which is a common technique in software testing, the three test cases provided (TC1 = 299,999, TC2 = 300,000, and TC3 = 300,001) cover the critical boundary values around the condition.

TC1 tests just below the boundary (299,999),

TC2 tests exactly at the boundary (300,000),

TC3 tests just above the boundary (300,001).

Since the software incorrectly checks for TAS equal to 300,000, only TC2 will fail because the condition is exactly met and highlights the incorrect implementation of the decision logic.