What mean “why if applicable?

Read this quotation when i do count the clock that tells the time. why is this verse an example of iambic pentameter?

The walls of valhalla were hung with shields; its ceiling glittered due to polished spearheads. read the passage. look at the underlined sections marked number (17). there may be a mistake in the way the sentence is written. if you find a mistake, choose the answer that corrects the mistake. if there is no mistake, choose ‘correct as is.’

What is the author's purpose in this passagea. to remind people to avoid individuals who occasionally display bad manners.b. to encourage people to embrace the feeling of superiority over others.c. to persuade people to demonstrate good manners at all times.d. to convince people to freely express their emotions.