Serena Williams should probably not mow her own lawn because a. her opportunity cost of mowing her lawn is higher than the cost of paying someone to mow it for her. b. she has a comparative advantage in mowing her lawn relative to a landscaping service. c. she has an absolute advantage in mowing her lawn relative to a landscaping service. d. she might sprain her ankle.

Using a cps-sample of 7,440 individuals, you estimate the following regression: = 20.91 - 2.61 x female where female is a binary variable that takes on the value of 1 for females and is 0 otherwise. the standard error on the coefficient on female is 0.25. the 95% confidence interval for the gender wage gap, or the amount that females earn less, is: a) [-3.10, -2.12] b) [18.30, 23.52] c) [-3.02, -2.20] d) [-1.96, -1.64]