Correct Answer: promptly

Solution : The most appropriate synonym is the first option.

Explanation : In the given sentence, the word rapidly is used to describe the rising demand for water. Rapidly implies a quick or swift increase, and the synonym that best captures this sense is promptly.

Promptly means without delay, quickly, or immediately, which aligns with the idea of a fast-paced increase in demand for water.

The meaning of the other options is as follows:

• Luxuriously : This term refers to something being done in a luxurious or indulgent manner.
• Leisurely : This word means something that is done at a slow, relaxed pace.
• Hopefully : This term expresses a sense of optimism or desire, which is not the meaning of "rapidly" in the given context.,
• The correct sentence would be: Demand for water is also promptly rising due to population growth, urbanisation, and increasing pressures from the agriculture and energy sectors.