Let A and B be two events in a random experiment with sample space such that P(B) ≠ 0 and P(A|B)=1. Which of the following is true ?

$A⊂B$ $B⊂A$ $A=\phi $ $B= \phi $

$A⊂B$

The correct answer is Option (1) → $A⊂B$ $P(B)≠0,P(A|B)=1⇒P(A∩B)=P(B)$ $⇒A⊂B$