Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Experiments revealed that caged starlings displayed a lack of directional sense and restless movements. B. Experiments revealed that caged starlings were unable to orient themselves in the direction of their normal migratory route. C. Experiments revealed that the restless movement of caged starlings had no clear direction. D. Experiments revealed that caged starlings' orientation was accurate unless the weather was overcast.