A retail company implemented a new 'incentive program' for sales staff, leading to a 20% increase in average monthly sales per employee. The CEO attributed this entire increase solely to the incentive program. For each statement, select the choice that best completes it.

The correct answer to the question "A retail company implemented a new 'incentive program' for sales staff, leading to a 20% increase in average monthly sales per employee. The CEO attributed this entire increase solely to the incentive program. For each statement, select the choice that best completes it." is Option C: A potential *alternative cause* for the sales increase could be: 'A recent expansion into a new, high-demand market.' A *necessary assumption* for the CEO's claim to be valid is: 'No other significant changes that could impact sales occurred simultaneously.'.

The other options — A) A potential *alternative cause* for the sales increase could be: 'A recent expansion into a new, high-demand market.' A *necessary assumption* for the CEO's claim to be valid is: 'No new competitors entered the market during this period.', B) A potential *alternative cause* for the sales increase could be: 'An unrelated national economic downturn.' A *necessary assumption* for the CEO's claim to be valid is: 'The incentive program was universally popular among staff.', D) A potential *alternative cause* for the sales increase could be: 'Reduced product pricing due to overstocking.' A *necessary assumption* for the CEO's claim to be valid is: 'Sales staff were previously underperforming.' — are incorrect for this GMAT Exam Prep question. As explained above: An alternative cause offers another plausible reason. A necessary assumption eliminates other factors as causes, ensuring the stated cause is the sole or primary driver for the observed effect.