The correct answer is C. It gives away electrons.
When a glass rod is rubbed with silk cloth, electrons are transferred from the glass rod to the silk cloth. This leaves the glass rod positively charged and the silk cloth negatively charged.
Option A is incorrect because protons are not transferred when a glass rod is rubbed with silk cloth. Protons are the positively charged particles in the nucleus of an atom.
Option B is incorrect because the atoms of the glass rod are not removed when it is rubbed with silk cloth. The atoms of the glass rod remain intact, but they are now missing some electrons.
Option D is incorrect because the glass rod does not give away positive charge. It gives away electrons, which leaves it with a positive charge.