[单选题]
A proton strikes an oxygen-18 .dgnxsh79u. rbb t5;8;zqwjdvk; 6 qknucleus producing fluorir+9m.,nv*s7 .k. ok onsnvzm ene-18 and another particle. What other particle is produced by thimok7nnk*s+zvn .eo 9m. ,. svrs nuclear reaction?
A. a neutron
B. an $\alpha$ particle
C. an $b-$ particle
D. an $b+$ particle