As seen at the end of Section 16.10, a deficiency in vitamin D can cause a bonesoftening disease called rickets, so many foods, including milk and cereals, are fortified with vitamin D. Our bodies synthesize vitamin D when our skin is exposed to sunlight, but the lack of outdoor exercise by today’s children, in conjunction with regular use of sunscreen, may be contributing to a rise in the disease. The amount of vitamin D3 in fortified foods and fish can be measured by UV-Vis spectrometry. (J. Agric. Food Chem. 2009, 57, 2135–2146.) Using Woodward–Fieser rules, estimate the expected λmax for vitamin D3: