[单选题]
The Q value for a particie)1; m,pdms lular8-pe 1wvbo aq9wf/z- c reaction is -2.4 MeV, and the reaction's threshold energy is 9.60 MeV. What is the ratio o o-bv/wpea 8c9q-w1fz f the mass of the incident particle to the mass of the stationary target nucleus?