Allegiance
ব্যাখ্যা
Question word 'Allegiance' means 'loyalty and support for a ruler, country, group, or belief'.
Ex: Soldiers have to swear allegiance to the Crown/the King.
The marked option 'Falsity' means 'the act or fact of violating the trust or confidence of another'.
Ex: Despite being offered a fortune to spill the president's secrets, the trusted aide declared that he'd sooner die than be guilty of such falsity.
From the above explanation, it's clear that 'Falsity' is the opposite in meaning to 'Allegiance'.
Therefore, the correct answer is option 4.