Answer:
d sub level starts from the 3rd energy level; means you can see electrons in d sub level in any energy levels after third one.
So the answer is "In any energy levels ≥ 3"
A simple information ; s sub level is in any energy level,
p sub level is in any energy level beginning from the 2nd energy level,
d sub level appears ≥ 3rd energy level
f sub level appears in 4th energy level and over.
Hope it helps!
#MissionExam001
