The correct answer is C. Force diagram.
A force diagram is a diagram that shows the point of application and line of action of forces in their plane. It is a two-dimensional representation of a three-dimensional system. The forces are represented by arrows, with the length of the arrow representing the magnitude of the force and the direction of the arrow representing the direction of the force. The point of application of the force is indicated by the head of the arrow.
A vector diagram is a diagram that shows the magnitude and direction of a vector. It is a two-dimensional representation of a three-dimensional vector. The vector is represented by an arrow, with the length of the arrow representing the magnitude of the vector and the direction of the arrow representing the direction of the vector.
A space diagram is a diagram that shows the three-dimensional position of points and objects. It is a three-dimensional representation of a three-dimensional system. The points and objects are represented by points, lines, and surfaces.
A funicular diagram is a diagram that shows the tension in the cables of a suspension bridge. It is a two-dimensional representation of a three-dimensional system. The cables are represented by lines, with the length of the line representing the tension in the cable.