Before a New Phone System Was Installed, the Amount a Company

Multiple Choice

Before a new phone system was installed, the amount a company spent on personal calls followed a normal distribution with an average of $700 per month and a standard deviation of $50 per month. Refer to such expenses as PCE's (personal call expenses) . Using the distribution above, what is the probability that during a randomly selected month PCE's were between $575.00 and $790.00?

A) .9579
B) .0421
C) .9999
D) .0001