Suppose C is a class that implements the interfaces I and J according to the diagram below.

C c $=$ null;

I i $=$ null;

J j $=$ null;

c $=$ i; $//$ line $1$

j $=$ c; $//$ line $2$

i $=$ j; $//$ line $3$

Given the above variable declarations, which lines below will require a cast?