Answer:
b. Integration testing.
Explanation:
An error condition consisting of an error in the passing of parameters; a method passes or returns an unexpected value such as a negative price, is usually found in Integration testing.
Integration testing can be defined as a phase in software applications testing, which typically involves the process of testing the interface between two software module combined as a group.
The main purpose of an integration testing is to determine the correctness of this interface and expose any fault existing between integrated modules.