A 100 W lamp is used for 6 hours daily for 30 days. Calculate the total energy consumed in kilowatt-hours (kWh) and choose the correct option.

The lamp is used for 6 hours daily for 30 days.

$$\text{Total time} = \text{Daily usage} \times \text{Number of days}$$ $$\text{Total time} = 6 \text{ hours/day} \times 30 \text{ days} = 180 \text{ hours}$$

The power of the lamp is 100 W.

$$\text{Energy consumed} = \text{Power} \times \text{Total time}$$ $$\text{Energy consumed} = 100 \text{ W} \times 180 \text{ hours} = 18000 \text{ Wh}$$

Since $1 \text{ kWh} = 1000 \text{ Wh}$:

$$\text{Energy consumed in kWh} = \frac{18000 \text{ Wh}}{1000 \text{ Wh/kWh}}$$ $$\text{Energy consumed in kWh} = 18 \text{ kWh}$$

Comparing this result with the given options:
[A] 18 kJ
[B] 18 kWh
[C] 1.8 J
[D] इनमें से कोई नहीं (None of these)

The calculated energy matches option [B].

The final answer is $\text{B}$.