The speaker says " we sing , but oh the clay is vile beneath our feet, and long the mile." (Lines 12-13) What is most likely interpretation of these lines

B. The people's lives are difficult, but they pretend to feel joy when others can see.

Explanation:

Paul Laurence Dunbar's poem "We Wear the Mask" refers to or talks about people who hide behind a mask to show the side that people want to see. But deep beneath the mask of happiness and smile that people can see, there is pain and suffering and crying, which is hidden so well by the mask.

The speaker talks about suffering which "hides our cheeks and shades our eyes". He then went on to state "We smile, but, O great Christ, our cries / To thee from tortured souls arise." And when he says "We sing, but oh the clay is vile / Beneath our feet, and long the mile;" he seems to say that despite the hardships faced by them, they will pretend to be joyful and show a happy face that everyone expects and wants to see, and he will hide his true feelings behind the mask.

Thus, the correct answer is option B.

the sentence that avoid faulty coordination is:

culture, which is well represented in philadelphia, plays a major role including theatre, music, and the visual arts.  

faulty coordination occurs when the writer gives equal importance two different ideas (clauses) which in fact are not equivalent. in order to correct a misplaced clause or idea, the writer can place less important or emphatic ideas in a relative clause as in the previous sentence.  

it is an infinitive phrase with a subject.