A car bulb connected to a 12-volt battery draws 2A  current while glowing. What is the resistance of the filament of the bulb?

To determine the filament of the bulb's resistance, use Ohm's law. This law explains the relationship between a current carrying conductor's resistance, voltage, and current.
Formula used:
The term used to describe Ohm's law is

$I=\frac{V}{R}$

Here, I stands for current flowing through the conductor, V for the potential difference between the conductor's two ends, and R for conductor resistance.

Ohm's law states that any difference in I between any two conductor points is precisely proportional to any difference in V that may exist between those locations and any other potential conductor points.
I∝V
⇒$I=\frac{V}{R}$…… (1)
The proportionality constant in this case is the conductor's resistance, R.
A battery with a potential difference (voltage) of 12 volts and a current of 2 A is connected to the automobile light. Determine the filament of the light bulb's resistance.
Rearrange equation (1) to reflect the bulb's filament resistance R according to Ohm's law.
⇒$R=\frac{V}{I}$
In the equation above, swap 2A for I and 12V for V.
$\Rightarrow R=\frac{12 \mathrm{V}}{2 \mathrm{A}}$
$\Rightarrow R=6\Omega$
Consequently, the bulb's filament's resistance is $6\Omega$.
Hence, the correct option is B.