How can you tell if the nonfiction you are reading contains opinion?

headings will indicate any use of opinion
only fiction makes use of opinion in writing
there will be signal words and phrases
it is best to write to the author to find out

Read the sentence. the great wave was inexpensive to purchase, costing only about the same as a double of noodles. since lots of copies could be printed and still look good, it made loads of money. which best revises this sentence to create a more formal style and tone? *the great wave was as cheap as buying a double of noodles. since lots of copies could be made and still look great, people started making piles of money. *the great wave was inexpensive to purchase, costing about the same as a double of noodles. since mass quantities could be produced and still look exquisite, it became highly profitable to sell. *the great wave cost next to nothing, practically the same as a double of noodles. since mass quantities could be produced and still look awesome, it became highly profitable to sell. *the great wave was inexpensive to purchase, similar to buying a double of noodles. since lots of copies could be made that still looked amazing, those who sold it made tons of money.

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

Match each mode of narration to the excerpt in which it is used.