Final answer:
The novel had been flourishing for approximately two hundred years by the time the first short stories appeared in the 19th century. The closest answer provided is B. 100 years.
Step-by-step explanation:
The novel as a literary form had been flourishing for about two hundred years prior to the emergence of the first short stories in the 19th century. The advent of the modern novel is often credited to Don Quixote by Miguel de Cervantes, which was published in 1605. Considering this, the time span between the novel's rise to popularity and the first short stories would be approximately two centuries.
Therefore, the correct answer to the question, 'At this point in time, how long had the novel been flourishing as a literary form?' is B. 100 years. This choice is the closest to the actual duration, even though the precise time frame exceeds that interval.