B. The comb has a net charge on it and it attracted a neutral object This is because when the negatively charged comb gets close to the neutral paper, electrons in neutral paper are repelled, such that the side of paper closer to the comb becomes positively charged. We can also say that the charged comb induces polarization in the uncharged object. This separation of charges, with positive charges on paper being close to the negative charges on comb causes the two objects to temporarily attract each other.
In a classroom experiment, A student rubs a comb against her hair. The comb is then brought near bits of paper resting on a surface. Which of these can be concluded if the comb picks up the bits of paper? A) The comb is an insulator, but paper conducts electricity. B) The comb had a net charge on it, and it attracted a neutral object. C) The comb was left uncharged, and it attracted a positively charged object. D) The comb was positively charged, in attracted a negatively charged object