Consider Three Different Systems $m$ And Equal Energy $3 m$ in System

Consider three different systems. Each consists of two particles that have equal mass $m$ and equal energy $3 m$ . In system $A$ , both particles move in the $+x$ direction. In system $B$ , the particles have opposite velocities. In system $C$ , the particle's velocities are at right angles to each other.
-Which system has the largest total mass?

A) System $A$
B) System $B$
C) System C
D) Systems $A$ and $B$ (which have equal total masses)
E) Systems $A$ and $C$ (which have equal total masses)
F) Systems $B$ and $C$ (which have equal total masses)
G) All three systems have the same total mass.