Jen is conducting an experiment involving a device known as a pith ball electroscope

the plastic ball hangs in mid air and is uncharged. charges cannot move alone the silk thread that holds the ball in the air.

jen completes the following steps in her experiment:
1. she collects three identical, uncharged rubber tubes.
2. she holds a magnet to the first tube for five mins
3. she submerges the second tube in a tank of water for 5 mins
4. she rubs the third tube with animal fur for 5 mins
jens teacher tells her that she can use the pith ball electroscope to see if any of the rubber tubes are surrounded by an electric field. what should jen do to test for an electric field surrounding each tube.

a, connect the three tubes to each other and see if they attract the plastic ball
b, hold the magnet in direct contact with the tube that was submerged in water
c, bring each tube close to the plastic ball and note any movement of the ball
b, bring the magnet close to the plastic ball and note the motion of the ball toward the magnet