To answer this question, we need to understand the concept of test design coverage. Test design coverage is a metric used to measure the extent to which the testable requirements are covered by the test cases created.
Let's go through each option to understand why it is correct or incorrect:
Option A) Test design coverage computes the number of test cases covered divided by the total number of test cases - This option is incorrect because test design coverage is not calculated by dividing the number of test cases covered by the total number of test cases. It focuses on the coverage of testable requirements, not the number of test cases.
Option B) Test design coverage computes the number of testable requirements covered divided by the number of test cases created - This option is incorrect because the denominator should represent the total number of testable requirements, not the number of test cases created.
Option C) Test design coverage computes the number of testable requirements covered divided by the number of testable requirements - This option is incorrect because the denominator should represent the total number of test cases, not the number of testable requirements.
Option D) Test design coverage computes the number of testable requirements covered by test cases created divided by the number of testable requirements - This option is correct because it correctly represents the calculation for test design coverage. It measures the coverage of testable requirements by dividing the number of testable requirements covered by the test cases created, by the total number of testable requirements.
Therefore, the correct answer is D. This option is correct because it accurately represents the calculation for test design coverage.