List of top Image Processing and Analysis Questions on 2D Convolution of Small Kernels

Which one of the following is the CORRECT outcome of convolution with zero padding of the two images given below?
\[ \begin{bmatrix} 1 & 1 \\ 1 & 1 \end{bmatrix} * \begin{bmatrix} 1 & 1 \\ 1 & 1 \end{bmatrix} \]