Correct Option (c)
The passage explicitly states that the United Nations Framework Convention on Climate Change (UNFCCC) places the responsibility for financial support on developed countries "taking into account their contribution to the stock of greenhouse gases (GHGs) in the atmosphere." This directly corresponds to statement 3, making it the sole reason provided within the passage for this allocation of responsibility.
Incorrect Options:
Statements 1 and 2 are not supported by the provided passage as reasons for assigning financial responsibility to developed countries.
- The passage does not mention "their higher level of per capita incomes" as a basis for the Convention's allocation of financial support.
- Similarly, the passage does not cite "their large quantum of GDP" as a reason for developed countries' financial obligations under the Convention.
The question specifically requires the answer to be based solely on the information presented in the passage, which identifies only the contribution to the stock of GHGs as the determining factor.