Which of the following statements about boundary value analysis is true?

a. It cannot be used to design test data to test the boundaries of output values

b. It leads to smaller amounts of test data being designed than equivalence partitioning

c. It is easier to undertake if decision trees rather than decision tables are used as the basis for test-data design

d. It is motivated by the empirical finding that logic errors often seem to occur at the boundaries of equivalence classes