The inverse of a conditional statement is, "If $\mathrm{ABC}$ is a triangle, then $\angle \mathrm{A}+\angle \mathrm{B}+\angle \mathrm{C}=180^{\circ}$ ". Then the contrapositive of the conditional statement is
(1) "If $\angle \mathrm{A}+\angle \mathrm{B}+\angle \mathrm{C}=180^{\circ}$, then $\mathrm{ABC}$ is a triangle.
(2) "If $\angle \mathrm{A}+\angle \mathrm{B}+\angle \mathrm{C} \neq 0$, then $\mathrm{ABC}$ is not a triangle.
(3) "If $\mathrm{ABC}$ is not a triangle, then $\angle \mathrm{A}+\angle \mathrm{B}+\angle \mathrm{C} \neq 180^{\circ}$.
(4) "If $\mathrm{ABC}$ is a triangle, then $\angle \mathrm{A}+\angle \mathrm{B}+\angle \mathrm{C}=180^{\circ}$.