Answer:
D.) independent variable on the x-axis
Explanation:
Normally in an x-y plane, the value of x is taken as an independent variable, i.e. it is independent because it can assume any value (real number), while y depends on the value x. for example for the following equation.
y = x
Where:
x = independent value.
y = dependent value of x
This is the equation of a line, inclined with slope equal to 1.