Read the excerpt below and answer the question that follows.

before march 1, 1989, the use of copyright notice was mandatory on all published works. omitting the notice on any work first published before that date could have resulted in the loss of copyright protection if corrective steps were not taken within a certain amount of time.

source: united states. copyright office. “copyright notice.” circular 3. washington, dc: library of congress, 2010. print.

this excerpt is from "copyright notice," an article found in circular 3, a publication of the united states copyright office.

what is the meaning of the word "mandatory" in the sentence above?
a. useful
b. optional
c. required
d. expensive

Which excerpts from the war of the worldseffectively use setting to provide a contrast to the horror of the plot? (select all that apply.)the war of the worldshe remained standing at the edge of the pit that the thing had made for itself, staring at its strange appearance, astonished chiefly at its unusual shape and colour, and dimly perceiving even then some evidence of design in its arrival. the early morning was wonderfully still, and the sun, just clearing the pine trees towards weybridge, was already warm.they shouted consolation and promises, and went off back to the town again to get . one can imagine them, covered with sand, excited and disordered, running up the little street in the bright sunlight just as the shop folks were taking down their shutters and people were opening their bedroom windows.it was glaringly hot, not a cloud in the sky nor a breath of wind, and the only shadow was that of the few scattered pine trees. the burning heather had been extinguished, but the level ground towards ottershaw was blackened as far as one could see, and still giving off vertical streamers of smoke.an enormous hole had been made by the impact of the projectile, and the sand and gravel had been flung violently in every direction over the heath, forming heaps visible a mile and a half away. the heather was on fire eastward, and a thin blue smoke rose against the dawn.