A stacked bar chart shows a company's revenue breakdown by product line (Alpha, Beta, Gamma) from 2018 to 2022. If the total height of the bars increased steadily, but the 'Alpha' segment's portion visibly shrank over the years, what does this indicate about Product Alpha's revenue contribution?

✓ Correct Answer: Option C

A shrinking segment within a growing stacked bar means its *proportion* decreased. Its absolute value could still increase if the total growth was substantial, decrease if total growth was small, or remain stable if its growth matched other lines' shrinkage. Option C covers all possibilities.