Property of Determinants:

1. Identical Rows: If any two rows (or columns) of a determinant are identical, its value is zero.
2. Reasoning: This can be proved by swapping the two identical rows. Swapping rows should negate the determinant ($D=-D^{\prime }$). But since the rows were identical, the determinant should remain the same ($D=D^{\prime }$). The only number satisfying $D=-D$ is $0$.