Which of the following occurs as a consequence of inert pair effect ?
a) `SnCl_(2)` acts as a reducing agent
b) `SnCl_(4)` acts as an oxidising agent
c) `SnO_(2)` is amphoteric
d) `PbO_(2)` is an oxidant
e) `CCl_(2)` is unstable but `PbCl_(2)` is stable