You are working on a project that was proceeding well until a manufacturing glitch occurred that requires corrective action. It turns out the glitch was an unintentional enhancement to the product, and the marketing people are absolutely crazy about its potential. The corrective action is canceled, and you continue to produce the product with the newly discovered enhancement. As the project manager, you know that a variance has occurred. Which of the following is true?

A. Common causes of variance, also known as special-cause variances, are situations that are unique and not easily controlled at the operational level.

B. Random variances, known or predictable variances, and variances that are always present in the process are known as common causes of variance.

C. Attribute inspection determines whether measurements fall within tolerable results.

D. Scatter diagrams display the relationships between an independent and a dependent variable to show variations in the process over time.