Explanation:

- The determinant of a product of matrices is the product of their determinants. For matrices A and B, \( |AB| = |A||B| \).

- Given \( |A| = -1 \) and \( |B| = 3 \), then \( |AB| = (-1)(3) = -3 \).

- Scalar multiplication affects determinants by raising the scalar to the power of the matrix's order. For a 3x3 matrix, \( |3AB| = 3^3 \times |AB| \).

- Calculate \( |3AB| = 27 \times (-3) = -81 \).

- Therefore, the determinant of \( 3AB \) is \(-81\).

The correct option is:

Option 3: -81