__________ can furnish proof during a criminal proceeding.

The correct choice is "evidence" because, in the context of a criminal proceeding, evidence refers to any type of material that can be presented in court to support the case of either the prosecution or the defense. Evidence can take various forms, including testimonial evidence from witnesses, physical evidence such as objects found at a crime scene, or documentary evidence like police reports or surveillance footage. Its purpose is to establish the truth of the matters presented in court, aiding the judge or jury in making informed decisions regarding the case.

While circumstances, facts, and statements can play critical roles in shaping a criminal case, they do not directly serve as proof on their own. Circumstances may provide context but require further substantiation. Facts are pieces of information, but evidence is what demonstrates these facts in the context of legal proceedings. Statements may relay information, but without being backed up by some form of admissible evidence, they lack the weight needed to substantiate a claim in court. Therefore, "evidence" is the definitive term that encompasses all means by which proof is provided during a criminal trial.