Which of the following cannot be the probability of an event?
(A) \( \frac{2}{3} \) (B) \( - 1.5 \)

(C) \( 15 % \) (D) \( 0.7 \)

\(\because \) The probability of an event E is a number P(E) such that

\( 0 \ \le \ P(E) \ \le \ 1 \)

\(\therefore \) -1.5 cannot be the probability of an event.

\(\therefore \) (B) is the correct answer.