Answer: The correct option is C.
Step-by-step explanation:
The given information or given figure,

Since angle DBC and DBA are supplementary angles.


DB is the common line in both triangle ABD and CBD

In both triangle the base and another side is same but the angle is different. As the angle increases the opposite side of the angle is also increases and vice versa.
Since the angle DBA is greater than angle DBC, therefore side AD>CD.
Thus, option C is correct.