If A,B,C are three events with $P(C)=0$ then $P(A \cup B \cup C )=$

Question

$\begin {array} {1 1} (1)\;P(A)+P(B) & \quad (2)\;P(A)+P(C) \\ (3)\;P(A)+P(B)-P(A \cap B) & \quad (4)\;None\: of \: these \end {array}$