The price elasticity of demand measures the responsiveness of the quantity demanded of a good or service to a change in its price. It is calculated as the percentage change in quantity demanded divided by the percentage change in price. In this case, we are given the initial and final prices and the corresponding quantities demanded, so we can calculate the price elasticity of demand using the following formula:

Price elasticity of demand = (Percentage change in quantity demanded) / (Percentage change in price)

Step 1: Calculate the percentage change in quantity demanded
The percentage change in quantity demanded is calculated as the difference between the final quantity demanded and the initial quantity demanded, divided by the initial quantity demanded, and then multiplied by 100.

Percentage change in quantity demanded = [(Final quantity demanded - Initial quantity demanded) / Initial quantity demanded] * 100

In this case, the initial quantity demanded is 300 and the final quantity demanded is 200.

Percentage change in quantity demanded = [(200 - 300) / 300] * 100 = (-100 / 300) * 100 = -33.33%

Step 2: Calculate the percentage change in price
The percentage change in price is calculated as the difference between the final price and the initial price, divided by the initial price, and then multiplied by 100.

Percentage change in price = [(Final price - Initial price) / Initial price] * 100

In this case, the initial price is Rs. 120 and the final price is Rs. 200.

Percentage change in price = [(200 - 120) / 120] * 100 = (80 / 120) * 100 = 66.67%

Step 3: Calculate the price elasticity of demand
The price elasticity of demand is calculated by dividing the percentage change in quantity demanded by the percentage change in price.

Price elasticity of demand = (Percentage change in quantity demanded) / (Percentage change in price)

In this case, the percentage change in quantity demanded is -33.33% and the percentage change in price is 66.67%.

Price elasticity of demand = (-33.33% / 66.67%) = -0.5

Since the price elasticity of demand is negative, we take the absolute value to get the magnitude.

Price elasticity of demand = 0.5

Step 4: Interpret the price elasticity of demand
The price elasticity of demand measures the responsiveness of quantity demanded to a change in price. In this case, the price elasticity of demand is 0.5, which means that for a 1% increase in price, the quantity demanded decreases by 0.5%. This indicates that the demand for movies at this theater is relatively inelastic, as a change in price has a proportionally smaller effect on the quantity demanded.

Conclusion:
The correct answer is option A) 0.8.

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