Birds startled by potential predators generally try to take cover in nearby vegetation. Yet many birds that feed at bird feeders placed in suburban gardens are killed when, thus startled, they fly away from the vegetation in the gardens and into the windowpanes of nearby houses. Which one of the following, if true, most helps to explain the anomalous behavior of the birds that fly into windowpanes? ['Most of the birds startled while feeding at bird feeders placed in suburban gardens are startled by loud noises rather than by predators.', 'The windowpanes of many houses clearly reflect surrounding vegetation.', 'The bird feeders in some suburban gardens are placed at a considerable distance from the houses.', 'Predator attacks are as likely to occur at bird feeders surrounded by dense vegetation as they are at feeders surrounded by little or no vegetation.']