Answer:
b. Unit Test
Explanation:
A unit test is done to test each individual component (often a program) to ensure that it is as defect-free as possible. It is one of the important level of software test in which every unit of a software is tested to validate that every unit has been designed well. Unit could be defined as the smallest part of a software which is testable and has one or more than one inputs and usually has only a single output. There are three types of unit testing which are Black Box testing, White Box testing and Gray Box testing. In black box testing only user interface, output and input are being tested, whereas in white box testing, every functions behavior is tested and in gray box testing execution of testes, their risks and assessment methods are being evaluated and tested.
