Answer for this MCQ on electricity

Dear Student
$R = \frac{V}{I}$
Here the slope is given by $\frac{I}{V}$ So its slope will give 1/R.
Hence more the slope less the value of Resistance hence is the best conductor.
The decreasing order of slope is  D>C>B>A
Therefore the decreasing order of resistance is as follows
 R_A> R_B> R_C> R_D
Option (a) is correct.

Regards