A. conducive
B. rare
C. useless
D. recent
Obsolete : no longer produced or used; out of date.
Conducive : making a certain situation or outcome likely or possible.
Rare : (of an event, situation, or condition) not occurring very often.
Useless : not fulfilling or not expected to achieve the intended purpose or desired outcome.
Recent : having happened, begun, or been done not long ago; belonging to a past period comparatively close to the present.
Antonym of Obsolete is Recent
