In an agricultural experiment, a large uniform field was planted with a single variety of wheat. The field was divided into many plots and the yield (lb) of grain was measured for each plot. These plot yields followed a normal distribution with mean 88 lb and standard deviation 7 lb. 92% of the plot yields were greater than what value?

64.11 lb

93.95 lb

78.13 lb

97.80 lb

82.05 lb

The answer is 78.13, but I cannot figure out why