I think B is best. I don't really like skinny, super tight jeans on anyone, so they're obviously not my thing with guys. Trousers or jeans that are fitted enough to show someone's shape whilst being loose enough to look comfortable and not constricting are the best :)
Slightly form fitting. If the wind blows and his pants come down because they're so baggy no thanks. If I know what his penis looks like without seeing him naked because his pants are so tight no thanks.
Dont wear baggy jeans especially hanging off your ass, i like my guy in fitted tapered jeans that kinda show is shape butt & pkg, If you wanna show your undie band or lack of- that is fine maybe these in a low rise type