1. **State the problem:** We are given the equation $x^2 + kx + 6 = (x + 2)(x + 3)$ and need to find the value of $k$ such that the equality holds for all $x$. 2. **Expand the right-hand side:** $$ (x + 2)(x + 3) = x^2 + 3x + 2x + 6 = x^2 + 5x + 6 $$ 3. **Compare both sides:** Since the expressions are equal for all $x$, their corresponding coefficients must be equal. 4. **Match coefficients of $x$:** From left: $kx$, from right: $5x$, so $k = 5$. 5. **Final answer:** $k = 5$. Thus, the correct choice is d. 5.