The detail that best supports the answer to Part A would depend on the question asked in Part A. However, if we assume Part A is asking about the key factors that contributed to the success and growth of the Green Belt Movement, the best supporting detail would be:
“In 1981, the Green Belt Movement got its first significant funding when the United Nations Development Fund for Women (UNIFEM) provided ‘seed money’ that transformed the effort from a few tree nurseries to a large number with thousands of seedlings.” (paragraph 12)
This detail highlights a critical moment of funding that allowed the movement to expand significantly, underscoring the importance of financial support in its development.