Topic: Miscellaneous (Others Question of English Grammer),

Best Answer Explained in Below-:

The phrase "If we want concrete proof, we are looking for ___" invites an interpretation of what "concrete proof" entails. The term "concrete" signifies something that is solid, verifiable, and tangible. In these contexts, "proof" usually refers to evidence or information that reliably demonstrates the truth of a claim or assertion.

Among the provided options, A) "clear evidence" directly aligns with this definition, as it encompasses the idea of irrefutable documentation or testimony that substantiates a point convincingly.

Conversely, the other choices do not fit the intent of the phrase: B) "building" refers to a physical structure, C) "a cement mixer" is a tool used in construction but unrelated to the concept of proof, and D) "something to cover a path" is vague and lacking relevance.

Thus, option A stands out as the most appropriate choice, as it encapsulates the essence of seeking solid and indisputable evidence, making it the only answer that truly aligns with the notion of "concrete proof."