Most people travel by air now-a-days because is cheaper and quicker .
A
when
B
during
C
it
D
by
Correct Answer: it
Because এরপর air এর পরিবর্তে pronoun হিসাবে it বসবে। বাক্যটি হবেঃ most people travel by air now a days because it is cheaper and quicker.