The correct answer is option 2. The Justice D.P. Wadhwa Commission was appointed to inquire into the murder of an Australian missionary and his sons. This indicates that the commission was specifically focused on investigating the circumstances and events surrounding the killing of the Australian missionary and his sons.

Option 1, which states violence against Christians in Gujarat, is not the correct answer. While violence against Christians did occur in Gujarat, it was not the primary focus of the Justice D.P. Wadhwa Commission.

Option 3, which mentions attacks on churches in M.P (Madhya Pradesh), is also not the correct answer. The commission was not appointed to inquire into attacks on churches in Madhya Pradesh specifically.

Option 4, burning of churches in Orissa, is also not the correct answer. The commission was not specifically appointed to investigate incidents of burning churches in Orissa.

Overall, it is important to note that the Justice D.P. Wadhwa Commission`s purpose was to investigate the murder of the Australian missionary and his sons, and not the other incidents mentioned in the other options.