The correct answer is C. The desire to improve education leads to a future in which students have to take aptitude tests as early as preschool.
Irony occurs when the opposite of what is expected happens. If you take a look at option C, the irony should be obvious. In their desire to improve education, people have started making very young children undergo vigorous tests to give them a better future, although that may not happen at all.
It is the rhythm of the song. In a similar way, all poems that are not written in free verse have rhythm, or a beat, as well. We also call that beat meter. Each specific syllable in a line of poetry is called a foot.
