(1) list grid, not here.

(2) Hypothetical reasoning:

Suppose a is lying, it can be concluded that b and c are telling the truth;

In this way, what B said is consistent with reasoning;

But what C said is wrong, because B didn't lie.

The assumption is wrong, that is, A is not lying and A is telling the truth.

Because A is telling the truth, it can be seen from A's words that both B and C are lies.

Which means two people are lying.

You can also assume that b begins to infer.

thank you