we know that
the x-intercept is when the y-coordinate is equal to zero
let
A (x,0)------> the x-intercept of the line l
the y-intercept is when the x-coordinate is equal to zero
let
B (0,y)------> the y-intercept of the line l
let
C (0,0)----> the origin
slope BA is equal to
mBA=(y2-y1)/(x2-x1)-------> mBA=(y-0)/(0-x)------> mBA=-y/x
in the right triangle ABC
tan ∅=opposite side angle ∅/adjacent side angle ∅
opposite side angle ∅=y
adjacent side angle ∅=x
so
tan ∅=y/x
see the attached figure to better understand the problem
therefore
the answer is the option D
tan ∅