If n=1 you divide by 2
If n=2 you divide by 4
If n=3 you divide by 8
so any n you divide by 2 to the power n
        
             
        
        
        
Hey there!:
Here the Statement - D is correct.  
Because Orbitals containing the core electrons are more attracted towards nuclear charge and hence less shilded from nuclear charge than an orbital that doesn't penetrate.  Also due to more attraction between the orbital containing core electron and nucleus, it will have less energy. 
Hope this helps!
 
        
             
        
        
        
Energy to lift something = 
               (mass of the object) x (gravity) x (height of the lift).
BUT ...
This simple formula only works if you use the right units.
Mass . . . kilograms
Gravity . . . meters/second²
Height . . . meters
For this question . . .
Mass = 55 megagram = 5.5 x 10⁷ grams = 5.5 x 10⁴ kilograms
Gravity (on Earth) = 9.8 m/second²
Height = 500 cm  =  5.0 meters
So we have ...
Energy = (5.5 x 10⁴ kilogram) x (9.8 m/s²) x (5 m)
            =  2,696,925 joules .
That's quite a large amount of energy ... equivalent to 
straining at the rate of 1 horsepower for almost exactly an 
hour, or burning a 100 watt light bulb for about 7-1/2 hours.
The reason is the large mass that's being lifted.
On Earth, that much mass weighs about 61 tons.