The correct answer is D. The arrows are drawn to scale from left to right.
A network diagram is a graphical representation of the sequence of activities in a project. Activities are represented by arrows, and the start and end of each activity are indicated by the tail and head of the arrow, respectively. The arrows are not drawn to scale, but rather are arranged in a logical order to show the dependencies between the activities.
For example, if activity A must be completed before activity B can begin, then the arrow for activity A would point to the arrow for activity B. The arrows are not drawn to scale, so the length of the arrow does not indicate the duration of the activity.
The network diagram is a useful tool for planning and scheduling projects. It can help to identify potential bottlenecks and conflicts, and to ensure that all activities are completed in the correct order.