A soft drink manufacturing and exporting company markets a new brand of a soft drink with two experimental flavors. Flavor 1 is sent to thirteen stores; the average sales in the first month is 45 units with a sample standard deviation of 7 units. Flavor 2 is sent to ten stores; the average sales in the first month is 38 units with a sample standard deviation of 6 units. Assume that the populations from which the samples are taken follow normal distribution.
State the null and the alternative hypotheses to test whether the data provide sufficient evidence to conclude that the mean sales per month of the soft drink with two flavors are different at α = 0.10.

a. 
H_{0}: μ_{1}  μ_{2} = 0 vs. H_{a}: μ_{1}  μ_{2} ≤ 0


b. 
H_{0}: μ_{1}  μ_{2} = 0 vs. H_{a}: μ_{1}  μ_{2} ≥ 0


c. 
H_{0}: μ_{1}  μ_{2} = 0 vs. H_{a}: μ_{1}  μ_{2} ≠ 0


d. 
H_{0}: μ_{1}  μ_{2} = 0 vs. H_{a}: μ_{1}  μ_{2} < 0


e. 
H_{0}: μ_{1}  μ_{2} = 0 vs. H_{a}: μ_{1}  μ_{2} > 0
