Radial Power System:
A radial power system is a type of electrical power distribution system in which power flows in one direction, from a single source to multiple loads. It is characterized by a single feed point or source, with distribution lines branching out to supply power to various loads.

Representation of Radial Power System:
The representation of a radial power system depends on the paths through which power flows. The given options for representing a radial power system are as follows:

a) Closed paths:
Closed paths refer to the presence of multiple interconnected loops or circuits within the power system. In a radial system, power flows in a single direction, and there are no closed loops or paths. Therefore, closed paths do not represent a radial power system.

b) Closed and open paths:
Closed and open paths represent a combination of interconnected loops and unidirectional flow. In a radial power system, power flows in a single direction, and there are no closed loops or paths. Therefore, closed and open paths do not represent a radial power system.

c) Only open paths:
Only open paths represent a unidirectional flow of power without any closed loops or interconnected paths. In a radial power system, power flows from a single source to multiple loads without any feedback or loops. Therefore, only open paths accurately represent a radial power system.

d) None of the other options:
This option suggests that none of the given options accurately represent a radial power system. However, as explained above, only open paths correctly represent the unidirectional flow of power in a radial power system. Therefore, option 'C' (Only open paths) is the correct answer.

In conclusion, a radial power system is represented by only open paths, as power flows in a single direction from a single source to multiple loads without any closed loops or interconnected paths.