Mean is one of those ordinary, everyday words with lots of different meanings. The adjective mean can describe someone who's stingy or ungenerous, but it also means "unkind or unfair," which is what a little kid intends to convey when she yells at her mother, "You're mean!"

Mean is a verb that refers to the action of conveying or expressing a particular idea or intention. It is used to describe the purpose or significance of something or to indicate what is intended or expected. The correct answer to the given question is option 'C', which states that "mean" is the correct form of the word in this context.

Meaning of the Word 'Mean'
The word "mean" has various meanings and can be used in different contexts. It is important to understand the intended meaning based on the context of its usage. Here are some common meanings of the word "mean":

1. Definition or Explanation:
- When we say "What does this word mean?", we are asking for the definition or explanation of the word. In this context, "mean" is used as a verb.

2. Significance or Purpose:
- The word "mean" can also refer to the significance or purpose of something. For example, "What does this action mean?" or "What is the meaning behind this symbol?"

3. Intent or Intention:
- "Mean" can also describe someone's intent or intention. For instance, "What did you mean when you said that?" or "I didn't mean to offend you."

Application of the Word 'Mean' in Different Forms
In the given question, the word is used as a verb. Let's understand the meaning and usage of each option to identify the correct answer:

a) Means:
- "Means" is the plural form of the word "mean" and is used as a noun. It refers to methods or resources used to achieve a particular goal. For example, "He used various means to reach his objective."

b) Meaning:
- "Meaning" is the gerund form of the verb "mean" and is used as a noun. It represents the definition or interpretation of something. For instance, "The meaning of this word is unclear."

c) Mean:
- "Mean" is the base form of the verb and is used when referring to the action of conveying or expressing a particular idea or intention. It is the correct form to use in the given question.

d) Is mean:
- "Is mean" is a verb phrase that combines the verb "is" (present tense of "to be") with the adjective "mean." This phrase describes someone as being unkind or malicious. For example, "He is mean to his classmates."

Therefore, option 'C' is the correct answer as it uses the verb form of the word "mean" in the given question.