Which linear function shows a direct variation?

Graph A

On a coordinate plane, a line goes through points (negative 1, 0) and (0, 2).
Graph B

On a coordinate plane, a line goes through points (0, negative 2) and (0, 1).

Graph C

On a coordinate plane, a line goes through points (0, 2) and (1, 0).

Graph D

On a coordinate plane, a line goes through points (0, 0) and (1, negative 2).
Graph A
Graph B
Graph C
Graph D

Graph B

Graph C shows a direct variation.