_ 3.- A research team went on the field to collect data on the height of hickory trees in Indiana. They recorded the heights of 120 hickory trees found in different parts of the state. The average height from this sample is 83 feet, with a standard deviation of 3 feet. They decided to calculate the 99% confidence interval to answer the question in the title, knowing that the standard deviation for the population is 5 feet. The confidence interval will have a margin of error of:

a.2.576*5/sqrt(120).

b.2.576*3/sqrt(120).

c.2.576*5.d. 2.576*3.

a.5/sqrt(120).f. 3/sqrt(120).