Two skaters, Skater 1 of mass \(m_1\) and Skater 2 of mass \(m_2\), stand facing each other at rest on a horizontal, frictionless ice surface. Skater 1 pushes against Skater 2, causing both skaters to move away from each other in opposite directions. For the system consisting of both skaters, which of the following correctly identifies the net external horizontal force \(\Sigma F_{\text{ext}}\) acting on the system during the push and the change in the total kinetic energy \(\Delta K\) of the system?