A projectile of mass \(M\) is launched from horizontal ground and travels along a parabolic path. At the apex of its trajectory, an internal explosion breaks the projectile into two fragments of masses \(m_1\) and \(m_2\), where \(m_1 \neq m_2\). Both fragments continue through the air without hitting the ground immediately, and air resistance is negligible. Which of the following diagrams best represents the trajectory (dashed curve) and instantaneous acceleration vector \(\vec{a}_{\text{cm}}\) of the two-fragment system's center of mass after the explosion?