Which one of the following is a 'National Political Party'?

Explanation:

The Bahujan Samaj Party (BSP) is India's third largest political party. For presenting Bahujans, or persons from the Scheduled Castes, Scheduled Tribes, and Other Backward Castes, as well as religious minorities this party was established.

Final Answer:

Hence, the correct answer is option (D) i.e. Bahujan Samaj Party.