Answer :

The glass rod losses electrons because the silk cloth has a positive charge so it attracts the negative charge of the glass rod. :) 

Explanation:

When a glass rod is rubbed against a silk cloth then both rod and cloth will get charged.

Since, it is given that the glass rod loses electrons this means that rod gets positively charged. On the other hand, silk cloth will gain the electrons as it is being rubbed by glass rod.

Therefore, silk cloth will get negatively charged.