According to Ohm’s law, the ratio of voltage to current in a conductor is constant.
Answer: Option A
Step-by-step explanation:
Ohm's law defines that an electric current flowing through the conductor between two ends is directly proportionate to the voltage at these two points. The introduction of a constant proportionality, resistance, gives a simple mathematical equation describing this relationship. Particularly, Ohm's law also mentions that R is constant in this respect, i.e. not dependent on the current.

Where,
I is the current conduction in amperes
V is the voltage calculated by the conductor in volts
R is the conductor’s resistance in ohms.