What shape denotes a pin on an action boundary?

What shape denotes a pin on an action boundary?

• A. Small square
• B. Small circle
• C. Diamond
• D. Triangle

Answer: (A)

Pins on an action boundary show where data enters or leaves an action in an activity diagram. The shape used for the pin signals its role: a small square marks an input pin, indicating data flowing into the action. This makes it easy to trace how inputs are provided to the action. A small circle would indicate an output pin, showing data produced by the action. Other shapes like a diamond or triangle are used for other diagram elements, not pins. So the small square is the symbol used to denote a pin on an action boundary.

Pins on an action boundary show where data enters or leaves an action in an activity diagram. The shape used for the pin signals its role: a small square marks an input pin, indicating data flowing into the action. This makes it easy to trace how inputs are provided to the action. A small circle would indicate an output pin, showing data produced by the action. Other shapes like a diamond or triangle are used for other diagram elements, not pins. So the small square is the symbol used to denote a pin on an action boundary.