A vector quantity has:

A vector quantity is defined by its characteristics of both direction and magnitude, along with the appropriate units that express its measurement. This means that when dealing with vector quantities, it is essential to recognize not only how much of the quantity there is (magnitude) but also the specific direction in which it acts. Therefore, being able to convey these two aspects, alongside identifying the necessary units, is crucial for comprehensive understanding in physics and engineering contexts.

For example, when discussing forces or velocities, stating not just the strength of the force (magnitude), like 10 Newtons, but also the direction, such as towards the east, is vital for accurate descriptions of physical phenomena and for performing calculations. The units also ensure that the quantities are expressed consistently and understood universally across various applications.

The other options either omit important components or do not fully encapsulate the defining attributes of vector quantities. For instance, only referencing magnitude alone would exclude the essential directionality that characterizes vector quantities.