The spanish settlers either in town or in ranches shared the common occupation of a) spreading christianity b) raising crops, cattle, and sheep c) searching for gold

Well even without prior research, our keyword is 'ranches' usually they will have crops and barns and such. But regardless, the answer is; (Edit.) The Spanish settlers in towns raised crops and animals to make money, and provide for their family rather than spending money on food everyday or week.

B) raising crops, cattle, and sheep

Use the formula: (n-2)×180, where n is the number of sides(18-2)×180= 28800, now this is the full exterior angle of 18-gon so you divide it by 18.28800÷18=160