Final answer:
In thin-layer chromatography (TLC), the mobile phase for the week's experiment is dichloromethane (DCM).
Step-by-step explanation:
In the context of thin-layer chromatography (TLC), the mobile phase refers to the solvent or solvent mixture that moves through the stationary phase, carrying the components of the mixture being analyzed. For the week's TLC experiment, the material that acts as the mobile phase is b. dichloromethane (DCM). This is because the stationary phase, typically a thin layer of silica, remains fixed on the TLC plate, while the solvent (dichloromethane in this case) moves through it, allowing the separation of different compounds based on their affinities for the stationary phase and their solubilities in the mobile phase.