Answer
(a) This orientation is not physically reasonable.
(b) This orientation is physically reasonable.
(c) This orientation is not physically reasonable.
Work Step by Step
(a) This orientation is not physically reasonable.
$v$ and $B$ are perpendicular to each other, and $F$ should be perpendicular to $v$
(b) This orientation is physically reasonable.
By the right hand rule, $v\times B$ should come out of the page (which it does in the diagram).
(c) This orientation is not physically reasonable.
$v$ and $B$ are perpendicular to each other, and $F$ should be perpendicular to $B$
