Answer:
B; North Sea
Step-by-step explanation:
So the answer is definitely not B, that's 2. You can tell by the shape and location.
I'm pretty sure that the Aegan sea is at 3. I could tell by the small, separated branch to the right (that's the Sea of Marmara)
Finally, the Mediterranean is around point 5, under the Aegan.
Hope I could help!