The correct answer is option 'C': Rf value.

Explanation:
The Rf value, also known as the retention factor value, is a measurement used in chromatography to determine the distance traveled by a substance in comparison to the distance traveled by the solvent. Here is a detailed explanation of the Rf value:

1. Chromatography:
Chromatography is a technique used to separate and analyze different components of a mixture based on their affinity for a stationary phase and a mobile phase. The stationary phase is a solid or liquid material that remains fixed in place, while the mobile phase is a liquid or gas that moves through the stationary phase.

2. Rf Value Calculation:
The Rf value is calculated by dividing the distance traveled by the substance from the baseline by the distance traveled by the solvent from the baseline. It is expressed as a decimal or a fraction. The formula to calculate the Rf value is as follows:
Rf value = Distance traveled by the substance / Distance traveled by the solvent

3. Significance of Rf Value:
The Rf value is a characteristic property of a particular substance under specific chromatographic conditions. It helps in the identification and comparison of different substances. By comparing the Rf values of known substances with those of unknown substances, one can determine the identity of the unknown substances.

4. Factors Affecting Rf Value:
Several factors can affect the Rf value, including the type of chromatography technique (e.g., thin-layer chromatography, paper chromatography), the composition of the stationary and mobile phases, temperature, and the nature of the compound being analyzed.

5. Uses of Rf Value:
The Rf value is widely used in various fields, including chemistry, biochemistry, forensic science, and pharmaceutical analysis. It is particularly useful in the identification of organic compounds, such as pigments, amino acids, sugars, and drugs.

In conclusion, the distance moved by the substance from the baseline to the distance moved by the solvent from the baseline is known as the Rf value. It is a crucial measurement in chromatography that helps in the identification and comparison of different substances.