Answer:
Verbal Irony.
Step-by-step explanation:
Verbal irony is described as the literary device when there is a discrepancy between the literal and implied meaning of the author's words. In the given sentence, the author uses the words 'competitors' to denote 'slaves' who are attempting diligently to please their owners('overseers') so that they might get better treatment or appraisal to the great house farm by using the idea of 'office seekers pleading to the political parties.' Thus, this contradiction between the words used and intended meaning suggests the use of verbal irony.