Which of the following statements about the Baisakhi festival is correct?

The correct option is It marks the harvest season in Punjab.

Explanation:
Baisakhi (also known as Vaisakhi) is a prominent spring harvest festival celebrated primarily in the Punjab region of Northern India. It signifies the time when rabi crops (especially wheat) are ripe and ready for harvesting, serving as a time of thanksgiving and celebration for farmers.

In addition to its agricultural significance, Baisakhi also holds immense historical and religious importance for Sikhs as it commemorates the formation of the Khalsa Panth by Guru Gobind Singh Ji in 1699.

Let's review why the other options are incorrect:
- It is celebrated only in winter: Incorrect, because Baisakhi occurs in the spring season (usually on April 13 or 14).
- It is a Buddhist festival: Incorrect, it is predominantly a Sikh and Hindu festival.
- It is observed during monsoon: Incorrect, monsoon arrives later in the year (around June to September).