D. is a difference of perfect squares because both terms 25x^2 and 36 is a square (5, x, and 6). Also, difference of perfect squares MUST have a minus sign.
I think the answer is Hinduism
1. according to the customs or usual practices associated with a particular society, place, or set of circumstances.
2. a written account of the customs of a manor or other local community or large establishment.
