What does the slope of the V-I graph represent?

The derivative technique may be used to determine a graph's slope. This indicates that the y-axis variable's change is divided by the x-axis variable's change. The slope in this case will be calculated as the velocity change divided by the current change. This could assist you in answering this query.
The fundamental idea needed to answer this topic is the ohm's law.
According to Ohm's Law, the current flowing through a circuit is determined to be directly proportional to the applied potential difference and inversely proportional to the circuit resistance. However, we can also state that doubling the voltage across a circuit will result in double the current.
$R=\frac{V}{I}$
Let's examine the voltage and current graph to find the answer to this puzzle.

Here, the x-axis is used to describe current in a conductor at constant temperature, while the y-axis is used to represent voltage. Given that the relationship is linear and ohmic, the graph of the current I against the potential difference V is a straight line with a constant slope of R. By the way, under some circumstances, such as when exposed to higher temperatures, practical resistors occasionally display non-linear behaviour.
From this, we may infer that the resistance of the circuit will be represented by the slope of this graph.

Hence, the correct answer is option D.