Here is the explanation for the correct answer:

I. Mineral oil is a major resource in Venezuela, which is known for its significant oil reserves. Therefore, the correct match is I-C.

II. Copper production is prominent in Zambia, which is one of the largest producers of copper in Africa. Hence, the correct match is II-A.

III. Manganese is a mineral that is majorly produced in Gabon, which is known for its rich manganese deposits. Therefore, the correct match is III-D.

IV. Bauxite production is significant in Guyana, which is known for its extensive bauxite reserves. Thus, the correct match is IV-B.

Therefore, the correct answer is: I-C, II-A, III-D, IV-B.