Which sentence is an appropriate and effective thesis for a persuasive essay on the topic of urban agriculture? a) although putting a garden in a city requires a lot of work, the benefits are well worth the time and energy. b) my class took a trip to one of the city gardens to learn about urban agriculture and it was very interesting. c) urban agriculture is an effective way of solving urban problem such as access to affordable produce and community isolation. d) there are many reasons to get involved in urban agriculture, the most important of which concern dangers to the environment.