Introduction:
In this question, we are asked to identify the festival that is not a religious festival. We are given four options: Lohri, Holi, Eid, and Christmas. Out of these options, we need to determine which one does not belong to the category of religious festivals.

Explanation:
To identify the festival that is not a religious festival, we need to understand the nature and significance of each festival.

Lohri:
Lohri is a popular Punjabi festival primarily celebrated in the Indian state of Punjab. It is associated with the harvest of crops and is celebrated with great enthusiasm. Although Lohri has cultural and traditional significance, it is not associated with any particular religion. Therefore, Lohri is not a religious festival.

Holi:
Holi is a Hindu festival celebrated predominantly in India and Nepal. It is known as the festival of colors and marks the arrival of spring. Holi has religious roots and is associated with various Hindu mythologies and legends. Therefore, Holi is a religious festival.

Eid:
Eid is an Islamic festival celebrated by Muslims worldwide. It marks the end of Ramadan, the Islamic holy month of fasting. Eid holds great religious significance for Muslims, as it commemorates the completion of their fasting and is a time of celebration and gratitude. Therefore, Eid is a religious festival.

Christmas:
Christmas is a Christian festival celebrated on the 25th of December every year. It commemorates the birth of Jesus Christ, who is considered the central figure of Christianity. Christmas is an important religious festival for Christians and holds great religious significance. Therefore, Christmas is a religious festival.

Conclusion:
Out of the given options, Eid and Christmas are religious festivals, while Lohri is not associated with any particular religion. Therefore, the correct answer is option C, Eid.