"He has a smile that could light up the world." - This is an example of -

• He has a smile that could light up the world. This is an example of - Hyperbole.

• Hyperbole:
- অতিরঞ্জন করা।
- An exaggerated statement or an extreme overstatement.
- Hyperbole is a figure of speech that uses an exaggerated or extravagant statement to create a strong, emotional response. As a figure of speech, it is not intended to be taken literally. Hyperbole is frequently used for humor.

- Example:

“I'll love you, dear, I'll love you
Till China and Africa meet,
And the river jumps over the mountain
And the salmon sing in the street," - (by W.H. Auden: As I Walk Out One Evening).

• He has a smile that could light up the world.
- উল্লিখিত বাক্যটি Hyperbole এর উদাহরণ।
- কারণ বাক্যটিতে অতিরঞ্জন করা হয়েছে, বাস্তবিক ভাবে কারো হাসি পৃথিবীকে অলোকিত করতে পারে না।

Other options,
• A comparison between two unlike things using 'like' or 'as' - Simile.
• Allusion: Allusion is an implicit or indirect reference to another work of literature, a historical or mythical person or event.
• Anapest:
- This is a poetic device defined as a metrical foot in a line of a poem that contains three syllables wherein the first two syllables are short and unstressed, followed by a third syllable that is long and stressed.
- For example: “I must finish my journey alone.” Here, the anapestic foot is marked in bold.

Source: An ABC of English Literature, Dr. M Mofizar Rahman.