2. For all complex numbers $z _ { 1 } , z _ { 2 }$ satisfying $\left| z _ { 1 } \right| = 12$ and $\left| z _ { 2 } - 3 - 4 i \right| = 5$, the minimum value of $\left| z _ { 1 } - z _ { 2 } \right|$ is:\\ (A) 0\\ (B) 2\\ (C) 7\\ (D) 17\\