The graph of the function f : R → R defined by f(x) = l x l is
A line lying in first and third quadrant
A pair of parallel lines
Symmetrical with respect to y - axis
A straight line
The graph of --------------- is a straight line parallel to y axis.
The graph of y = a is
(a) the x - axis
(b) the y - axis
(c) a line parallel to y - axis
(d) a line parallel to x - axis