Why did small towns and cities begin to pop up? Group of answer choices? if you don't know don't answer, and do not tell me to go to a website

A. Settlers wanted the lifestyle of a city and wanted nothing to do with farms.

B. People settled where they could sell goods or offer services to settlers on farms.

C. Over the years, people lost the skills required to farm and had to find other jobs to do.

D. Every last piece of farmland was taken, so towns and cities were the only choices.