Answer:
red
Step-by-step explanation:
Adjacent angles are angles that share a common vertex without overlapping
( to be more specific they are angles that are right next to each other )
∠BOD and ∠AOC are not next to each other, they are vertical angles therefore dark blue is not the answer
∠COB and ∠DOA are not next to each other but vertically aligned with each other ( vertical angles ) therefore cyan is not the answer
∠COB and ∠AOD are the same as ∠COB and ∠DOA therefore yellow is not the answer
∠AOD and ∠AOC are right next together and share a common vertex without overlapping each other therefore red is the correct answer