What is meant by the standard of proof?

3. What is meant by the standard of proof?
Standard of proof or level of proof, refers to the quality of evidence produced to
establish a fact. In a sense it indicates as to how strongly the evidence establishes
the fact it purports to prove. Generally the following three levels of proof are referred
to in judicial/legal proceedings:
(a) Preponderance of probability
(b) Clear and convincing evidence
(c) Proof beyond reasonable doubt