Which of the mirrors depicted above is a plane mirror?

Read this excerpt from leah missbach day's foreword to wheels of change.as wbr's resident photographer i am privileged to see firsthand the impact bicycles have on the lives of our recipients.why does the author include this excerpt?

The greatest gift the sumerians gave the world was the invention of writing. the sumerians were a wealthy people. they needed some way to keep track of what they owned. they began drawing pictures. they used a reed as a pen. they drew on soft pieces of clay. the soft clay was then dried in the sun. the tablet became a permanent record. later, the sumerian drawings changed into wedge-shaped symbols. this kind of writing is called cuneiform. by putting symbols together, the sumerians could write entire sentences.

In the excerpt above, what can be inferred by the statement, "the dillingham had been flung to the breeze during aformer period of prosperity.?