Refactoring, as it applies to the practice of extreme Programming (XP), refers to:

A.
Restructuring the estimate by applying a higher cost performance index during ¡°what if¡±
analysis.

B.
Modifying the project due to scope changes, resource availability, and cost and schedule
variances.

C.
Modifying the cost baseline due to an increased estimate at completion and a negative
cost variance.

D.
Restructuring of code so as to improve the code without changing its external behavior.