Find determinants of matrices A=$\begin{bmatrix}a & 3 & 0 & 5\\0 & b & 0 & 2\\ 1 & 2 & c &3\\ 0&0&0&d \end{bmatrix}$ and B=$\begin{bmatrix}x & y& z & t\\2 & 1 & 1 & 2\\ 2 & 3 & 1 &4\\ 1&3&2&3 \end{bmatrix}$.

I tried to reduce the matrix A by forming a triangular matrix but i could get anything concrete.