Step 1: Understanding the question.
COP15 is the 15th meeting of the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC). It was held in Copenhagen in December 2009.
Step 2: Analyzing the options.
(A) 15th Copenhagen climate change December 2009: This is partially correct but lacks the full description of the event.
(B) 15th Conference of Parties to the United Nations Framework Convention on Climate Change: Correct — This is the full name of COP15.
(C) 15th Meeting of the Parties to the Kyoto Protocol: Incorrect, as COP15 is not limited to the Kyoto Protocol, but rather a broader climate change conference.
(D) 15th Conference on Climate Change Global Risks, Challenges and Decisions held at Bella Centre, 2009: Incorrect, though it provides details about the event's venue and topics.
(E) 2009 United Nations Climate Change Conference: This is also a correct description but does not match the full formal name.
Step 3: Conclusion.
The correct answer is (B) 15th Conference of Parties to the United Nations Framework Convention on Climate Change.