To answer this question, the user needs to know about Capability Maturity Model (CMM) and its different levels.

CMM is a framework that defines the key elements required for building and improving software development processes. It provides a structured approach to improve an organization's software development process by defining the stages of a maturity model. There are five levels of CMM, ranging from level 1 to level 5, with each level indicating a higher degree of process maturity.

Now, let's look at each option and determine which one is the correct answer:

A. CMM Level 2: This level is also known as the repeatable level. At this level, the software development process is characterized by basic project management techniques, and successful practices are repeated from project to project. However, it does not include optimization, defect prevention, and quality control.

B. CMM Level 3: This level is known as the defined level. At this level, the software development process is characterized by the existence of a set of defined and documented standard processes and procedures. It includes optimization, defect prevention, and quality control.

C. CMM Level 4: This level is known as the quantitatively managed level. At this level, the software development process is characterized by quantitative management of the process and product. It includes optimization, defect prevention, and quality control.

D. CMM Level 5: This level is known as the optimizing level. At this level, the software development process is characterized by continuous process improvement and optimization. It includes optimization, defect prevention, and quality control.

From the above explanations, it is clear that the correct answer is:

The Answer is: D. CMM Level 5.