Answer:

Introduction:
Clicking the mouse is a basic action performed on a computer to interact with items on the screen. By clicking the mouse, we can select, open, and interact with various objects, such as icons, files, folders, and applications.

Explanation:
When we click the mouse, we can perform different actions, depending on the number of times we click. In this case, the correct answer is option 'b', which means that double-clicking the mouse opens an item on the computer.

Single-click:
A single click refers to pressing and releasing the left mouse button once. Single-clicking is often used to select an item or activate a menu option. It is not typically used to open an item directly.

Double-click:
Double-clicking refers to quickly pressing and releasing the left mouse button twice in succession. This action is commonly used to open items, such as files, folders, or applications. When we double-click an item, the associated program or action is triggered, and the item opens.

Triple-click:
Triple-clicking refers to quickly pressing and releasing the left mouse button three times in succession. This action is not typically used to open items but can be used in certain applications to select an entire paragraph or block of text.

None of these:
The option 'd', "None of these," is incorrect because single-clicking and triple-clicking are not the actions commonly used to open items on a computer. Only double-clicking is widely recognized as the action to open an item.

Conclusion:
In summary, clicking the mouse is a fundamental action on a computer, and double-clicking is the action commonly used to open items. By double-clicking an item, such as a file or folder, we can trigger the associated program or action and open the item on the computer.