Should teenagers be treated as adults

Which techniques best describe the tone the author is using in this passage?

Which verb or verb phrase signals an inappropriate shift in mood. a) will you let b) should first change c) must attend d) will be served

The greatest gift the sumerians gave the world was the invention of writing. the sumerians were 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.