three ships a,b,c are in motion . hte motion of a as seen by b

Question

Three ships A,B & C are in motion . The motion of A as seen by B is with speed v towards north-east. The motion of B as seen by C is with speed v towards the north -west. Then as seen by A,C will be moving towards -

[a] north

[b] south

[c] east

[d] west