While the novel's plot was undeniably ______, its character development remained largely ______, preventing it from achieving truly classic status.

✓ Correct Answer: Option B

The structure implies a contrast: the plot has one quality, but the character development has a contrasting negative quality ('preventing it from achieving truly classic status'). 'Convoluted' (complex and difficult to follow) for plot, and 'rudimentary' (basic, underdeveloped) for character development, fit this negative contrast.