Just FYI, the "with" in C and D is redundant. It should be "with who/whom did you go."
– DJMcMayhemMay 09 '15 at 19:49
Though *"With who did you go?" is ungrammatical. ("Who did you go with?" is fine.)
– May 09 '15 at 22:12
"With whom did you go?" -- if you want to use "whom", place the preposition before it (consider it a rule). In America, at least in daily English, "whom" is hardly ever used. Almost never. B is correct.
– Michael RybkinMay 10 '15 at 17:12