It should be the first choice.
Become
Base Form:Become
Past Simple:Became
Past Participle:Become
3rd Person Singular:Becomes
Present Participle/Gerund:Becoming
Answer:
I think the opposite is loose
Explanation:
Because responsible is being able to be trusted to do a task right? So loose would be the opposite since if you're loose(crazy,out of control,ect) you wouldn't be trusted as being responsible
