Final answer:
The sound of the word 'cow' is a symbol for a cow, whereas the sound of the word 'moo' is a sign for the sound a cow makes.
Step-by-step explanation:
The correct answer is c) symbol; sign. In the question, 'representation' and 'symbol' are often used interchangeably, but they have slightly different meanings. A representation is something that stands for or represents something else, while a symbol is a specific type of representation that carries a deeper meaning.
In this context, the sound of the word 'cow' is a symbol for a cow because it represents the sound that a cow makes. Similarly, the word 'moo' is a sign for the sound a cow makes because it directly imitates or represents that sound.