While the Picture Box tool is included in the form, a triangle appears in the upper-left corner of the control?

Edit Box
Property Box
Task box
Image box

The correct answer is: Image box.

A triangle appears in the upper-left corner of an image box when the Picture Box tool is included in the form. This indicates that the image box is selected and can be edited.

An edit box is a control that allows users to enter text. A property box is a window that displays the properties of a selected control. A task box is a window that displays the tasks that can be performed on a selected control.

I hope this helps! Let me know if you have any other questions.