Answer: A. X-rays
Explanation:
X-rays have the shortest wavelength and the highest energy of all of the options given. 
 
        
             
        
        
        
The solution for the problem is:
1 Watt = 1 Joule per second 
1 Watt*second = 1 Joule 
a Kilowatt is 1,000 Watts 
an hour is 60 seconds times 60 minutes or 3,600 seconds 
a Kilowatt * hour is 1,000 Watts in 3,600 seconds 
15 W*h = 15,000 Watt*hour = 15,000 Watt * 3,600 seconds = 54,000,000
Watt*second 
54,000,000 Watt*second = ? Joules 
54,000,000 Joules / second = 54,000,000 Watts
 
        
             
        
        
        
 <span>It's close to the sun without much atmosphere, so it's characterized by </span><span>very extreme temperatures.
Happy studying ^_^</span>
        
             
        
        
        
Potential if it is off or kinetic energy when its on