Evaluate the line integral∫cf⋅dr, where f(x, y,z)=xi−4yj−zkf and c is given by the vector function r(t)=⟨sint, cost, t⟩, 0≤t≤3π/2.

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

Where is your question?