Question 119490
{{{pi*d}}} will be plotted on the y-axis
{{{d}}} will be plotted on the x-axis
The slope is (change in y) / (change in x)
If {{{x=10}}}, {{{y = 10*pi}}}
If {{{x=50}}}, {{{y = 50*pi}}} etc.
The slope is {{{pi}}}
so, (b) is correct