The correct answer is B. Door.
A door is a movable barrier that allows people and objects to pass through an opening in a wall, fence, or other barrier. Doors are typically made of wood, metal, or glass, and they can be either hinged or sliding. Hinged doors swing open and closed on hinges, while sliding doors move horizontally along tracks. Doors can be locked to prevent unauthorized access, and they can also be equipped with security features such as peepholes and deadbolts.
The other options are incorrect because they are not typically used to lock, shut, or fasten things. A window is an opening in a wall or roof that allows light and air to enter a building. An iron is a heavy metal that is used to make tools and other objects. A block is a solid piece of material that is used to support or hold something in place.
Here is a table that summarizes the information about each option:
| Option | Description | |---|---| | Door | A movable barrier that allows people and objects to pass through an opening in a wall, fence, or other barrier. | | Window | An opening in a wall or roof that allows light and air to enter a building. | | Iron | A heavy metal that is used to make tools and other objects. | | Block | A solid piece of material that is used to support or hold something in place. |
