Write the element stiffness matrix for a beam element.

• A. K=\(\frac{2EI}{l}\)
• B. K=\(\frac{2EI}{l}\begin{bmatrix}2 & 1 \\ 1 & 2 \end{bmatrix}\)
• C. K=\(\frac{2E}{l}\begin{bmatrix}2 \\ 1 \end{bmatrix}\)
• D. K=\(\frac{2E}{l}\begin{bmatrix}1 & 1 \\ 1 & 1 \end{bmatrix}\)