Which of the following is an appropriate description concerning program test?
a) It is better to assure software quality during the test phase than to improve it during
the design phase.
b) When a program is modified after completion of the test, it is better to test the
program by using both the original and additional test data.
c) It is better to exclude test data that triggers an error in the program, because the
purpose of the test is to confirm that the program works without any errors.
d) It is better for programmers to design and execute the test cases without any
assistance from other persons.