The line of greatest slope on an inclined plane P1 is that line in the plane which is perpendicular to the line of intersection of plane P1 and a horizontal plane P2.
The coordinates of a point on the plane 2x+y−5z=0 that is 11 units away from the line of intersection of the given two planes are
a. (3,1,−1)
b. (−3,1,1)
c. (3,−1,1)
d. (1,3,−1)