Gold Miners in Alaska Have Found,on Average,12 Ounces of Gold

Multiple Choice

Gold miners in Alaska have found,on average,12 ounces of gold per 1000 tons of dirt excavated with a standard deviation of 3 ounces.Assume the amount of gold found per 1000 tons of dirt is normally distributed. If the miners excavated 1000 tons of dirt,how little gold must they have found such that they find that amount or less only 15% of the time?

A) -1.04
B) 1.04
C) 8.88
D) 15.12