It’s letter B, the left part is the first part of the equation we see one triangle which is 4 and we 2 squares which equals to 2x, this gives us the first part which is 2x+4. The right part is the second part of the equation, we have 3 triangles which we have to multiply times 4 (4•3=12), we have one square which is equal to x, we put this together and we get x+12. Finally you put everything together to get the final answer which is 2x+4=x+12