The . . . . . . . . symbol is used to take a decision in the flowchart.

The correct answer is D. Diamond.

A diamond symbol is used to represent a decision point in a flowchart. It is a four-pointed shape with rounded corners. The diamond is used to indicate that the flow of the program will branch depending on the outcome of a condition.

The other options are incorrect because they are not used to represent decision points in flowcharts.

• Ovals are used to represent the start and end of a flowchart.
• Rectangles are used to represent processes or actions.
• Parallelograms are used to represent data or files.