Firebrick tire company wants to increase sales of its long

Question

Firebrick Tire Company wants to increase sales of its long running, low-end Roadmaster Tire brand with anew advertising campaign promoting they will last at least 28,000 miles [Mu=28,000 miles].  Tests with arandom sample [n=30 tires] show a sample mean [x=27,5000 miles] with a sample standard deviation [s=1664.8026 miles].  At a .05 level of significance, these tests indicate

a. Reject H_o: Z of -1.6450 = -1.6450

b. Do no reject H_o: Z of -1.6450 = -1.6450

c. The sample results are too close to either Reject H_o: or to not reject H_o:

d. The sample data are NOT conclusive.  Conduct another sample.

e. None of the above answers is correct