Critical Reasoning (CR) | The mayor of Rome recently began an advertising campaign that discoura

The mayor of Rome recently began an advertising campaign that discouraged the feeding of pigeons in the city's historic squares. Since the beginning of the campaign the number of pigeons recorded in the city by municipal employees has fallen by over 15%. Clearly the advertising campaign is having the desired effect and the pigeons are moving out of the city in search of food.

Which of the following, if true, casts the most serious doubt on the conclusion drawn above?

a) Since the beginning
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