He has been studying --- morning
A
from
B
since
C
for
D
after
Correct Answer: since
Present perfect continuous tense এ point of time বুঝালে preposition since হয়। প্রদত্ত বাক্যে morning দ্বারা point of time বুঝাচ্ছে। সঠিক উত্তর - since.