Answer:
d) shortening the string
Explanation:
Time period of a pendulum clock is dependent on two factors namely:length and acceleration due to gravity. 
 When a clock loses time, the time period of the pendulum clock increases.
 This however can be corrected by decreasing the length of the pendulum.The time period of the pendulum clock is not dependent on the mass of the bob. The time period of the pendulum clock can be corrected only by changing the length of the pendulum string.
 
        
                    
             
        
        
        
So,
GPE (graviational potential energy) = mass x g x height
GPE is depends on where zero height is defined.  In this situation, we define h = 0 as the initial height.



The builder has gained 18.375 kJ of PE.
 
        
        
        
Normally a storm surge.
Experience: I lived through Andrew and Wilma