The correct option is A True
Given, ∠ABC=90o and ∠CDB=90o
In △ABC,
∠BAC+∠ABC+∠ACB=180o
∠BAC+∠ACB+90o=180o
∠BAC+∠ACB=90o...(I)
In △ABD,
∠ABD+∠ADB+∠BAD=1806o
∠ABD+∠BAD+90o=180o
∠ABD+∠BAD=90o...(II)
Equating I and II
∠BAC+∠ACB=∠ABD+∠BAD
∠ACB=∠ABD (Since, ∠BAC=∠BAD)
∴∠ABD=∠C