Final answer:
A point is a location in space with no size. Only a single electric-field line can exist at that point, illustrating its infinitely small characteristics. In contrast, distance is a scalar with magnitude but no direction, and displacement is a vector with both magnitude and direction.
Step-by-step explanation:
A definition of a point according to geometry is option a) A location in space with no size. A point has no dimension and is often described as just a position on a plane or in space with no length, width, or height. Options b) and c) define a line and a plane respectively, while option d) refers to a specific case wherein two lines meet. Within the context of physical science, such as physics or chemistry, the term point could be used to describe an infinitely small location in space where an event or measurement, like electric-field lines or electron density, is considered. For example, only a single electric-field line can exist at any given point in space, and a point in an electron wave where there is zero electron density is known as a node.
It is also useful to distinguish between scalar and vector quantities in physics. Distance is a scalar and has magnitude but no direction, while displacement is a vector and includes both magnitude and direction. A scalar can be negative, such as a -20°C temperature but still does not have a direction associated with it.