To minimize disk I/O, which of these should be chosen? CHAR, VARCHAR

Answer: Option B

This question is about choosing the right data type in MySQL to reduce how much your database needs to read and write data from your computer's hard drive (disk I/O). This is important because less disk I/O means your database runs faster!
Let's break down the options:
* CHAR: This data type stores fixed-length strings. It means that no matter how long your actual text is, CHAR will always reserve the same amount of space.
* VARCHAR: This data type stores variable-length strings. It means that VARCHAR only uses as much space as your actual text needs.
So, which one minimizes disk I/O?
Option B: VARCHAR is the better choice because it uses less space than CHAR. Remember, less space means less data to read and write, leading to less disk I/O and a faster database.
Why not CHAR?
CHAR, although simple, can waste space. If you have a short string like "cat" stored in a CHAR(10) field, you'll still reserve 10 characters worth of space, even though you only used 3. This wasted space leads to more disk I/O.
In Summary:
For storing strings of varying lengths, VARCHAR is generally the best option to minimize disk I/O and improve database performance.