Final answer:
The fourth syntactic indicator for identifying a noun is the presence of articles such as 'a,' 'an,' and 'the,' which are typically used to introduce nouns in sentences.
Step-by-step explanation:
The fourth syntactic indicator to determine whether a word is a noun or not is C. Presence of articles. Articles like 'a', 'an', and 'the' often precede nouns in English. Morphological endings can help indicate parts of speech, as can word position to some extent, and pronunciation can affect the form of a word but these are not primary syntactic indicators of a noun. Instead, articles often help to signal that a word is a noun because they are used to define or introduce a noun within a sentence.