To solve this question, the user needs to have basic knowledge of mainframe environments and their capabilities to access DB2.

Now let's go through each option and explain why it is right or wrong:

A. TSO - This environment can access DB2. TSO (Time Sharing Option) is an interactive dialog with the operating system, which provides an interface for the user to interact with the system. DB2 can be accessed through TSO environment using SPUFI and QMF tools.

B. CICS - This environment can access DB2. CICS (Customer Information Control System) is a transaction processing system that can access DB2 databases to store and retrieve data.

C. IMS - This environment can access DB2. IMS (Information Management System) is a hierarchical database management system that can access DB2 databases using the DLI (Data Language Interface) module.

D. ENDEVOUR - This environment is a software change management tool and does not have the ability to access DB2.

Therefore, the correct answer is:

The Answer is: D. ENDEVOUR