Task: Question Answering
Input (English): 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?  
 (A) the solubility of the components in the mobile phase (B) the evaporation rate of the components at a certain temperature (C) the magnetic property of the components (D) the thickness of the paper used as the stationary phase
Output (English): A