题目下列函数中,()是微分方程 y'' - 7y' + 12y = 0 的解.A. y = x^3B. y = x^2C. y = e^3x下列函数中,()是微分方程 $y'' - 7y' + 12y = 0$ 的解.A. $y = x^3$B. $y = x^2$C. $y = e^{3x}$题目解答答案C. $y = e^{3x}$