At the time of short circuit, the electric current in the circuit:

In a series combination of electrical components, there is only one continuous path for the flow of electric charge. Consequently, the electric current ($I$) remains the same through all parts of the circuit, regardless of the individual power ratings or resistances of the connected devices.

Since the $100\text{ W}$ bulb and the $40\text{ W}$ bulb are connected in series, the current flowing through both bulbs must be identical. Given that the current through the $100\text{ W}$ bulb is $1\text{ A}$, the current through the $40\text{ W}$ bulb is also exactly $1\text{ A}$.

• Options A, B, and C are incorrect because they assume the current divides or changes based on the power ratings of the bulbs, which only occurs in a parallel connection.