Let a sample space be $S = \{\omega_{1}, \omega_{2}, \ldots, \omega_{6}\}$. Which of the following assignments of probabilities to each outcome is valid?

Outcome	Probability
$\omega_{1}$	$1/8$
$\omega_{2}$	$2/3$
$\omega_{3}$	$1/3$
$\omega_{4}$	$1/3$
$\omega_{5}$	$-1/4$
$\omega_{6}$	$-1/3$

(NONE) For an assignment of probabilities to be valid,it must satisfy two conditions:
$1$. Each probability $P(\omega_{i})$ must be such that $0 \le P(\omega_{i}) \le 1$ for all $i$.
$2$. The sum of all probabilities must be equal to $1$,i.e.,$\sum_{i=1}^{6} P(\omega_{i}) = 1$.
In the given assignment,we observe that $P(\omega_{5}) = -1/4$ and $P(\omega_{6}) = -1/3$.
Since these probabilities are negative,they violate the first condition $(0 \le P(\omega_{i}) \le 1)$.
Therefore,this assignment of probabilities is not valid.