43 points pls help select the question mark Choose the answer that tells the main problem in the story

Answer this correctly what is the cause and effect

The rich natural resources made the sacramento valley a "garden of eden." permanent villages were established about 8,000 years ago. which choice combines these two sentences from paragraph two to achieve a coherent flow of ideas? a) the rich natural resources made the sacramento valley a "garden of eden" and permanent villages were established about 8,000 years ago. b) permanent villages were established about 8,000 years ago and the rich natural resources made the sacramento valley a "garden of eden." c) the rich natural resources made the sacramento valley a "garden of eden; " and so the permanent villages were established about 8,000 years ago. d) because of the rich natural resources which made the sacramento valley a ‘garden of eden,’ native americans established permanent villages there 8,000 years ago.

In which two sentences does the author use an ironic tone toward the subject