Answer:
(a)
Conservative
(b)
Not conservative
(c)
Conservative.
Step-by-step explanation:
(a)

Notice that

and

Therefore the field is conservative.
(b)
Notice that

and

but

Therefore is not conservative.
(c)
Notice that
To prove that the vector field is conservative you have to compute the curl of the vector field and you would get that.


Therefore your vector field is conservative.
I believe it is c because it is definitly not biased because they were selected at random. And d. Is incorrect
I believe you go to the spots on the graph and then just found up from there, and do that with every point