Answer:
January
Explanation:
The month October is the 10th month,
there is 12 months in a year
2451 / 12 = 204.25
0.25 of a year, 1/4 of the year so 12/4 = 3
2451 months is 204 years and 3 months
3 months after October is January
10 + 3 = 13 where December is 12 and the 13th month is January