Explanation

Ghana (A) was the first sub-Saharan African country to gain independence from colonial rule, achieving this on March 6, 1957, under the leadership of Kwame Nkrumah from British rule. Nigeria (B) gained independence later, in 1960. Chad (C) also gained independence in 1960, making it later than Ghana. “None of these” (D) is incorrect because Ghana is the correct answer.