Mark M. answered • 03/04/21

Retired Math prof. Experienced Math Regents tutor.

B and C are parallel since they have the same slope (-1/5) and have different y-intercepts.

A is perpendicular to both B and C since the slope of A (5) is the negative reciprocal of the slopes of both B and C.

D s neither parallel nor perpendicular to A, B, and C