Answer:
A. 1974 litres.
Explanation:
To calculate the total water usage in a week, we need to multiply the average daily water usage per house by the number of houses and the number of days in a week (7).
Average daily water usage per house is given as 47 litres.
Total water usage in a week = Average daily water usage per house * Number of houses * Number of days in a week
Plugging in the given values, we get:
Total water usage in a week = 47 litres * 6 houses * 7 days
Total water usage in a week = 1974 litres
Therefore, the correct answer is option A. 1974 litres.