Give conditions on $a$, $b$ and $c$ so that the line integral of the vector field $\vec F = \vec i + a\vec j + b \vec k$ on the curve $C$ is negative, if $C$ is the line segment from $(3,1,4)$ to $(c,1,4)$.

$a$ ? < <= = >= >
$b$ ? < <= = >= >
$c$ ? < <= = >= >
(For each, pick the correct relationship and enter the appropriate value in the answer blank. If there is no restriction on a parameter, select = for the relation and enter anything in the answer blank.)