please help me answer the question

USF is interested in learning about the average time it takes students to drive to campus. USF sampled 238 students and asked each to provide the amount of time they spent traveling to campus. This variable, travel time, was then used to create a confidence interval and to conduct a test of hypothesis, both of which are shown in the printout below.

One-Sample T Test Null Hypothesis: mu = 20 Alternative Hyp: mu > 20  95% Conf Interval Variable Mean SE Lower Upper T DF P TravelTime 23.243 1.3133 20.655 25.830 2.47 237 0.0071 Cases Included 238 

What alternative hypothesis should be test to determine if the mean travel times of all students exceeds 20 minutes?

mu differs from 20

mu < 20

mu = 20

mu > 20