Answer:
Static electricity.
Explanation:
Electric Charge; Is the quantity of electricity held in an object
The balloon is electrically neutral, meaning it had an equal amount of positive and negative charges hence it couldn't attract the paper.  
After rubbing the balloon, it gained an electric charge; and after gaining this charge it got the ability to exert a force on the pieces of paper and attract them, This is called static electricity.
Therefore, Static electricity caused the paper to stick to the balloon.  
 
 
        
             
        
        
        
1. D:Asteroids have geological activity
2.A:Short-period comets circle around the sun in 200 years or less and originate in the Kuiper Belt
3.D:All of the above
4.A:It’s gravity is too weak to clear it’s orbit
5.B:Ceres
6.C:Haumea
7.A:Is bigger than Pluto 
I hope this helps
        
             
        
        
        
R = 2.06 mm = 2.06 x 10^(-3) m
Q = 1.6 x 10^(-19) C
v = 2.5 x 10^(-5) m/s
I = 8 A = 8 C/s
A = r² π = ( 2.06 x 10^(-3) ) ² x 3.14 = 13.325 x 10^(-6 ) m² =
= 1.3325 x 10^(-5) m²
I = n Q v A
n = I / (Q v A)
n = 8 C/s / ( 1.6 x 10 ^(-19) * 5.4 x 10^(-5) * 1.3325 x 10^(-5) ) = 
= 0.694 x 10^(29) m^(-3)
n = 6.94  x 10^(28)   m^(-3)
        
                    
             
        
        
        
<span>So we want to know when do we have enough information about the atom that we can say that it is electrically neutral. So the information we need to know is the number of protons, whic are positively charged particles and the number of electrons which are negatively charged particles. Number of protons has to be equal to number of electrons for the atom to have neutral charge. Neutrons are electrically neutral so their number doesn't change the charge of the atom. So the correct answer is B. </span>