Answer:
B
Step-by-step explanation:
I can only see part of the question can you repost it?!!
Given :
Two vectors :

To Find :
The value of b for which the vectors are orthogonal .
Solution :
We know , two vectors are orthogonal when the are perpendicular to each other .
So , their dot product will be zero .
So ,

Therefore , for b =0 and
the vectors are orthogonal .
Hence , this is the required solution .
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