A significant of a whole through its significant part is

Analyze the question: The question is asking for the figure of speech in which a significant part stands for the whole. The wording is a little garbled ("significant of a whole"), but the meaning is clear: a part represents the whole thing.

Explain the concept: Let's look at each option.

• Allegory: A story or narrative with a hidden, deeper meaning, usually moral or political. Example: Animal Farm. It is not about a part representing a whole.
• Pun: A play on words that exploits a word's multiple meanings or similar sounds. It has nothing to do with part and whole.
• Synecdoche: A figure of speech in which a part is used to represent the whole (or, less commonly, the whole represents a part). Examples: "All hands on deck" (hands = sailors), "He asked for her hand in marriage" (hand = the whole person), "The school has over 500 heads" (heads = students).
• Cast: This is not a figure of speech. It refers to the actors in a play.

Solution:

1. The question describes a part standing for the whole.
2. That is the exact definition of synecdoche.
3. The other options don't match: allegory is an extended symbolic narrative, pun is wordplay, and cast is a group of actors.

Answer: The correct option is C. synecdoche.

Exam tip: Remember the link "Synecdoche = Small part for the Sum." Also keep it separate from metonymy, which substitutes something closely associated with the thing (e.g., "the crown" for the monarchy). In synecdoche, the item is literally a part of the whole.