The correct option is D New year
Option C: The occasion of New Year is mentioned in these lines "The year is dying in the night...the year is going, let him go". The 'year is going' means that the year is ending. Hence C is the correct option.
Thanksgiving, and Christmas are festivals which the poem does not describe. Similarly, summer is a season, but there's no mention or description of summer.
Hence options A, B and D are incorrect.