Can anyone explain the answer to this basic Physics question for me.?
 

A positively charged glass rod attracts object x. The net charge of object x ...
A) may be zero or negative,
B)may be zero or positive,
C)must be negative,
D)must be positive

The answer is a. I thought it was c. I understand why the answer cannot include positively charged, but how can it be zero?
Thank you.
Oh is that polorization?