Answer : 3. "Kilobyte"
Explanation :

1. The smallest memory is the parity bit. A bit is a binary digit, which can be either 0 or 1. A bit is the smallest unit of data that a computer can store.

2. A byte is a large unit of memory made up of 8 bits. A byte can be used to store a letter, a number or a symbol.

3. Kilobyte is another large unit of memory which is made up of 1024 bytes. One kilobyte can be used to store a small file.

4. A megabyte is another large unit of memory which is made up of 1024 kilobytes. One megabyte can be used to store a large file.

5. Gigabyte is another large unit of memory which is made up of 1024 megabytes. One gigabyte is equal to the amount of memory used in a medium-sized computer.

5. Terabyte is another large unit of memory which is made up of 1024 gigabytes. One terabyte is equivalent to the amount of memory used in a large computer.