The sentence that is the least fluent is B. Sampson, a horse trainer, has participated in the last four Olympics even though they were banned by the committee
Explanation:
Sentence fluency is the rhythm and pace of each and every word and its composition as we read it since a read word needs to have cadence, rhythm, power, and movement. Whenever the composition is awkward or has dissonant parts it breaks the fluency and makes it hard to read and understand to the reader. This sentence has so much unnecessary data that breaks the pace many times.
