Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: Paper chromatography is a process used to separate mixtures of substances into their components. The components are carried by a mobile phase through a stationary phase made of absorbent paper. An investigation analyzed a sample of black ink to determine its components.Which property allows the components to separate?
the solubility of the components in the mobile phase
Polarity.