Michelangelo' s sixteenth-century Sistine Chapel paintings are currently being restored. A goal of the restorers is to uncover Michelangelo' s original work, and so additions made to Michelangelo' s paintings by later artists are being removed. However, the restorers have decided to make one exception: to leave intact additions that were painted by da Volterra. Which one of the following, if true, most helps to reconcile the restorers'decision with the goal stated in the passage? ['Michelangelo is famous primarily for his sculptures and only secondarily for his paintings, whereas da Volterra is known exclusively for his paintings.', "Da Volterra's work is considered by certain art historians to be just as valuable as the work of some of the other artists who painted additions to Michelangelo's work.", 'The restorers believe that da Volterra stripped away all previous layers of paint before he painted his own additions to the Sistine Chapel.', 'Because da Volterra used a type of pigment that is especially sensitive to light, the additions to the Sistine Chapel that da Volterra painted have relatively muted colors.']