Art restorers who have been studying the factors that cause Renaissance oil paintings to deteriorate physically when subject to climatic changes have found that the oil paint used in these paintings actually adjusts to these changes well. The restorers therefore hypothesize that it is a layer of material called gesso, which is under the paint, that causes the deterioration.

Which of the following, if true , most strongly supports the restorers' hypothesis?

• ARenaissance oil paintings with a thin layer of gesso are less likely to show deterioration in response to climatic changes than those with a thicker layer.  
• BRenaissance oil paintings are often painted on wooden panels, which swell when humidity increases and contract when it declines.  
• COil paint expands and contracts readily in response to changes in temperature, but it absorbs little water and so is little affected by changes in humidity.  
• DAn especially hard and nonabsorbent type of gesso was the raw material for moldings on the frames of Renaissance oil paintings.  
• EGesso layers applied by Renaissance painters typically consisted of a coarse base layer onto which several increasingly fine-grained layers were applied.