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 $900 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 $775.00 and $990.00?

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