Which answer corrects the error in capitalization?
in the month of february, washington's birthday is an official federal holiday.
a.
federal
b.
february
c.
official
d.
birthday

  I think your answer would be B. February. Because it's the name of a month. We capitalize things like the names of our presidents, a famous place, or even a restaurant.
 We can also capitalize the days of the month and days depending on the sentence.