The derivative of \( f(x) = 3x^2 + 4x + 5 \) is calculated using the power rule. The derivative of \( 3x^2 \) is \( \frac{d}{dx}(3x^2) = 6x \). The derivative of \( 4x \) is \( \frac{d}{dx}(4x) = 4 \). The derivative of the constant 5 is 0. Combining these, the derivative of \( 3x^2 + 4x + 5 \) is \( f'(x) = 6x + 4 \). The correct answer is option (1).