An important step in the software lifecycle is testing. One type of testing is integration testing. Which of the following is not true concerning integration test?

A$.$ Integration testing is employed to integrate separately tested pieces.

B$.$ In a top$-$down integration test, testing begins at the top levels to see whether the overall logical design works and the interfaces between modules are correct.

C$.$ In a bottom up integration test, testing begins first at the lowest level sub$-$programs. A test driver is used to set$-$up the testing environment by declaring and assigning initial values to variables and then calls the sub$-$program to be tested.

D$.$ In integration testing, either a top$-$down or a bottom$-$up approach is selected to complete the test.