The themes of Biraha songs often include:

Pain of separation
Social injustice
Devotion to deities
Celebration of nature

The correct answer is: Pain of separation.

Biraha songs are a type of folk song that is popular in the Indian states of Bihar and Jharkhand. They are typically sung by women and are often about the pain of separation from a loved one. The songs can be very emotional and can be used to express a wide range of emotions, such as sadness, longing, and anger.

Here is an example of a Biraha song:

“O my beloved, where have you gone?
I am waiting for you, but you do not come.
The days and nights pass slowly,
And my heart is filled with pain.

I have lost my appetite,
And I cannot sleep at night.
I am like a bird without wings,
Who cannot fly to you.

O my beloved, come back to me soon!
I cannot live without you.
I am like a flower without water,
Who will soon wither and die.”

Biraha songs are an important part of the culture of Bihar and Jharkhand. They are a way for people to express their emotions and to connect with each other. The songs are also a way to preserve the history and traditions of the region.

The other options are also important themes in Biraha songs, but they are not as common as the theme of pain of separation. Social injustice is sometimes a theme in Biraha songs, but it is usually not the main focus of the song. Devotion to deities is also sometimes a theme in Biraha songs, but it is usually not as important as the theme of pain of separation. Celebration of nature is not a common theme in Biraha songs.