Passage Summary: Experts can tell which artist created a drawing by looking at specific techniques like shading and outlines. This method proved that several drawings thought to be by Michelangelo were actually made by a different artist named Clovio.

Reasoning: Stylistic features like hatching and contours allow experts to distinguish between different artists, leading to the discovery that some 'Michelangelo' drawings were actually done by Giulio Clovio.

Analysis: Since this is a Must be True question, we need to find a statement that is logically guaranteed by the premises. We are told that stylistic analysis 'can help to distinguish' works by different artists and that this specific analysis successfully separated Clovio's work from Michelangelo's. This implies a necessary condition: Michelangelo and Clovio must actually have different styles regarding those specific features. If their hatching and contours were identical, the analysis described would have been unable to tell them apart. Look for an answer that confirms a stylistic difference exists between these two specific individuals.