Answer:
Option C, 18,000 J/s
Explanation:
Watt is an SI unit of power. Also joules per second is another unit of power. As both watt and joule per second are equivalent to each, they represents the same physical quantity i.e "power"
Therefore 18000 watt can be simply written as 18000 Joules per second.
The frequency value provided here is an additional numerical figure and has no role in conversion of watt to joule per second.
Hence option C is correct.