C. the ability to do something well without wasted time or effort
The speaker's tone in "Harlem" is best described as frustrated.
The poem's imagery helps to convey this tone. In discussing a deferred dream, Hughes describes a dried up raisin in the sun; a festering sore; stinking, rotting meat; and a sagging, heavy load. At the end of the poem, he wonders if the deferred dream just explodes.
This imagery helps provide the key to understanding the speaker's attitude, or tone, about his subject, the deferred dream. He is frustrated that these dreams are wasted.
A random sample is a subset of individuals that are randomly selected from a population of interest. Because researchers usually cannot obtain data from every single person in a group due to time, costs and other constraints, a smaller portion is randomly chosen to represent the entire group as a whole. The goal is to get a sample that is representative of the larger population.
