Given 3 formulas A,B,C , which answer is correct:
a) $(A \models (B \Rightarrow C) ) \Leftrightarrow ((A \Rightarrow B) \models C)$
b) $(A \models (B \Rightarrow C) ) \Leftrightarrow (A \models C)$
I tried to rewrite $\models$ by $\Rightarrow$ and make truth tables , but I have not found anything in that tables what could help me solve this.