The answer is C. She does not want the reader to believe that the couple is perfect. Hope this helps =)
Each roll is independent to the others, and there is a 1/6 (16.7%) chance that a 6 is rolled. so you multiply each roll's probability together:
1/6 x 1/6 x 1/6 x 1/6 = 0.00077
The aspect of historical context that this excerpt most reflects is a development in technology.
Bicycles were the most popular means of transport before the car was invented, but when first automobiles started to appear, everybody noticed how much more effective those were in comparison to bicycles. That is why more and more cars were produced, and fewer and fewer bikes.
