Explanation:

- Expansion refers to the process of growing, increasing, or extending in size, volume, or scope. It often involves spreading out or becoming larger.

- Option 1: Inflation usually refers to the rate at which prices for goods and services rise, causing money to lose its value. It's not directly related to physical size but more to economic concepts.

- Option 2: Augmentation means the process of making something greater by adding to it. It's synonymous with increasing or enhancing.

- Option 3: Extension involves making something longer or larger in terms of time or space. It's akin to expansion.

- Option 4: Compression is the process of reducing the size, volume, or amount of something. It involves pressing or squeezing together.

Compression is the opposite of expansion as it signifies reduction or decrease in size.