If A and B are events such that P(A/B) = P(B/A) ≠ 0, then:

The correct answer is Option (4) → $P(A) = P(B)$ ##

Given:

$P\left(\frac{A}{B}\right) = P\left(\frac{B}{A}\right)$

$⇒\frac{P(A \cap B)}{P(B)} = \frac{P(B \cap A)}{P(A)}$

$⇒\frac{P(A \cap B)}{P(B)} = \frac{P(A \cap B)}{P(A)}$

$⇒P(A) = P(B)$