Doge is a farming company with innovative food-growing practices. Leafy greens are grown in small, self-contained and climate-controlled racks. They are interested in testing the hypothesis that their racks achieve a yield of 28.5 pounds of produce per square foot. They measure the output of 400 racks and find an average yield of 27.9 and a standard deviation(Sample) of 4. What is the t-statistic corresponding to this hypothesis?

A) -3

B) -4

C) 4

D) 3