To explain the trend in tourist revenue from 1990 to 2010, we need to identify the option that does not provide a plausible explanation. Let's analyze the options provided:

A. The number of total hotel rooms has increased.
This can be a possible explanation for the increase in tourist revenue. If the number of hotel rooms has increased, it suggests that there is more accommodation available for tourists, potentially attracting more visitors and generating higher revenue.

B. The number of tourists has increased from 1990 to 2010.
This can be a possible explanation for the increase in tourist revenue. If the number of tourists has increased over time, it indicates a larger customer base, which can contribute to higher revenue.

C. Average stay per tourist has increased.
This can be a possible explanation for the increase in tourist revenue. If the average stay per tourist has increased, it implies that tourists are spending more time at the hotel, which can lead to higher revenue.

D. The average price of tourist services has increased.
This can be a possible explanation for the increase in tourist revenue. If the average price of tourist services has increased, it suggests that tourists are paying more for their accommodations or other services, resulting in higher revenue.

E. Average expenditure per tourist has increased.
This can be a possible explanation for the increase in tourist revenue. If the average expenditure per tourist has increased, it indicates that tourists are spending more money on various services, contributing to higher revenue.

Based on the analysis, there is no option that does not provide a plausible explanation for the trend in tourist revenue. Each of the options can potentially explain the increase in revenu