Answer:
The sign on the fence
Explanation:
All elements of the cartoon: the size of the cow's sign, the cow holding the sign, the fence holding the cows and the comment of the cow standing in four legs are all important and contribute to the overall message. However, the most effective element in the cartoon's message is the content of the sign on the fence: It is concise, precise and has the capacity to achieve a result, such as to catch people's eyes and to be memorable.
