Answer: Affix.
An affix is a grammatical unit that is attached to a word's stem to form a new word. They are important in English because they are one of the main ways in which the language creates new words.
The two most common ones are: prefixes, which are placed before the stem (ex. pre-, in-, un-) and suffixes, which are placed after the stem (ex. -ly, -ness).
In A: it should be "I was" not "I were".
In B: it should be "lately you appear" not "you appears"
in C: this is correct! the subject is in agreement with the verb, and this is the correct answer.
in D: it should be "you are"
The narrative perspective determines by whom the story is actually told; most common are. a first person narrator, which means the narrator is also a character in the story who gives his or her view on what is happening. As a consequence, you don't always know how other characters think or feel.