--- They prefer to walk to the shop rather than_______ in their cars.

A. to go        B. going        C. go  

质子、中子和氘核的质量分别为m₁、m₂和m₃，真空中光速为c，当质子和中子结合成氘核时，放出的能量是[ ]

A．m₃c²

B．(m₁+m₂)c²

C．(m₃-m₂-m₁)c²

D．(m₁+m₂-m₃)c²