Which of the following cannot be the probability of occurrence of an event?

(ii) and (iv) can’t be the probability of occurrence of an event. So, (ii) and (iv) are the answers to our question.

Explanation: We know that

$0 \leq$ probability $\leq 1$ i.e. probability can vary from 0 to 1 (both are inclusive)

So, (i) 0 can be possible as $0 \leq$ probability $\leq 1$

(ii) $-\frac{3}{4}$ 4 is not possible as it is less than 0

(iii) ${ }^{\frac{3}{4}}$ is possible as $0 \leq$ probabilty $\leq 1$

(iv) ${ }^{\frac{4}{3}}$ is not possible as it is greater than 1

Conclusion: $\frac{4}{3}$ and $-\frac{3}{4}$ are the probabilities that cannot occur.