1) You were supposed to use mobility of electrons to explain the pith ball's attraction to the glass rod. This could be done in two ways: a) ball was negative because it gathered some excess mobile electrons from the black rod earlier or b) ball was neutral but some electrons on ball moved to the side closer to the glass rod so the ball had a charge distribution with some excess negative charge closer to the positive rod than the excess positive on the opposite side of the ball.
2) You were asked to explain what happened in observations D1 and D2 not just describe them.
3) Many of you said your finger in D led to a positive charge on the scope, allowing electrons to escape. This is correct. But then in your next answer you said it neutralized the scope in B and D. This is true for B but clearly not D. In both B and D it did serve as a path for electrons to leave the scope, but in D this led to a charged, not neutral scope.
4) You were asked to compare the charge on the object causing the charge with the charge on the object being charged. This is a general question and does not refer to a particular experiment. Thus, negative and positive are not possible answers since it is not known if the object doing the charging is positively or negatively charged. The correct answers are: for conduction, the object doing the charging and object becoming charged have same charge; for induced charge, the objects will have opposite charges.
5) For the rod and two spheres: the two spheres are not grounded and the rod does not touch sphere A. Therefore the total number of electrons on the two spheres is equal to the total number of protons. However the negative rod near A will push some electrons onto B. If you move A and B apart before the rod is removed from the vicinity of A, then B will retain the excess electrons and A will be missing the same number, so A is + and B is -.
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