Probability distributions are characterized by two important measures: central tendency and dispersion. Expected value or mean of the distribution is most often utilized to measure central tendency. The following probabilities of various losses for a certain risk are: $0 loss with a probability of 0.50, $100 loss with a probability of 0.30, $500 loss with a probability of 0.15 and a $1,000 loss with a probability of 0.05. The mean or expected loss given this probability distribution is _______.

(a) $155.00

(b) $400.00

(c) $38.75

(d) $151.25