[单选题]
The Feynman diagram showsf m -u;(klv:mllb1b1 r3wml b+ two electrons approaching eb,c3 ,tuv b-5igso vq7ach other, interacting, and then leaving each other. What particle is being exchanged during the interacti7-5gvtv o,q,su3bic bon?
A. pion
B. virtual photon
C. neutrino
D. $W$ particle
