The correct answer is B) the yellowish-white glare on the underside of a cloud layer. "Ice blink" refers to the yellowish-white glare that appears on the underside of clouds when there is a surface of sea ice below. This glare is caused by the reflection of sunlight off the smooth, flat surface of the ice, which produces a distinctive illumination on the clouds above. The other options are incorrect because they do not accurately describe the phenomenon of "ice blink." Option A refers to "water sky," which is a different nautical term. Options C and D describe the appearance of clouds over open water, which is different from the effect of sea ice.