A student rubs identical balloons in the same way with different materials. The student wants to determine the sign and compare the amount of charge on each balloon. Two experimental methods are used. The first is to count the number of identical bits of paper that can be picked up by each balloon. The second is to bring each balloon to the same distance from the top of a positively charged electroscope and observe whether the leaves move together or apart and how much they move. Which of the following correctly indicates what information could be obtained by analyzing the results from each method? a. Number of pieces of paper Motion of leaves
sign and amount of charge sign of charge only

b. Number of pieces of paper Motion of leaves
amount of charge only sign and amount of charge

c. Number of pieces of paper Motion of leaves
amount of charge only sign of charge only

d. Number of pieces of paper Motion of leaves
sign of charge only amount of charge only