Answer:
A. facial expressions and speech balloons.
Step-by-step explanation:
These are the elements that the author uses the most in order to convey the central idea of these panels. The author uses facial expressions in order to show the feelings and thoughts of the characters. The characters appear sad, distressed or shocked based on their facial expressions. The author also conveys the central idea of these panels by providing speech balloons that inform us of the conversations that are taking place between the characters.