When storing Renaissance oil paintings, museums conform to standards that call for careful control of the surrounding temperature and humidity, with variations confined within narrow margins. Maintaining this environment is very costly, and recent research shows that even old oil paint is unaffected by wide fluctuations in temperature and humidity. Ttherefore, museums could relax their standards and save money without endangering their Renaissance oil paintings. Which of the following is an assumption on which the argument depends? ['Renaissance paintings were created in conditions involving far greater fluctuations in temperature and humidity than those permitted by current standards.', 'None of the materials in Renaissance oil paintings other than the paint are vulnerable enough to relatively wide fluctuations in temperature and humidity to cause damage to the paintings.', 'Most Renaissance oil paintings are stored in museums located in regions near the regions where the paintings were created.', 'Under the current standards that museums use when storing Renaissance oil paintings, those paintings do not deteriorate at all.']