Step 1: Understanding the Question.
The question is asking about a key concept in cell structure theory. The correct answer corresponds to the contribution of Oparin and Haldane in the origin of life theory.
Step 2: Analyzing the Options.
(A) Oparin and Haldane: Correct — They are known for their hypothesis on the chemical origins of life.
(B) Carl Ernst von Baer: Baer was known for his work in embryology, not the origin of life.
(C) The theory of evolution: While evolution is key in biology, this question is about cell structure.
(D) Oxygen theory: Not correct for this context.
Step 3: Conclusion.
The correct answer is (A) Oparin and Haldane, as they proposed a theory on the origin of life.