Final answer:
The blank in the quote from Charlotte Bronte should be filled with 'Monday' to complete the phrase "unromantic as Monday morning."
Step-by-step explanation:
Charlotte Bronte wrote, "unromantic as Monday morning." Therefore, the correct answer to fill in the blank is (a) Monday.
This line is from Charlotte Bronte's novel "Shirley." Bronte was a writer during the Romantic Period, but here she contrasts the excitement often found in Romantic poetry with the drabness and routine associated with a Monday morning.
This choice of day reflects a common sentiment toward Monday, often seen as the most unromantic and mundane day of the week due to it being the start of the work and school week.