Sue: Commercial flights currently contribute more carbon dioxide... Dave: Did you know that by taking one inter-continental flight... Dave's response to Sue's comment serves to
A. reinforce Sue's contention that flights are a major contributor to increased carbon dioxide levels
B. add more weight to her contention that we should reduce the number of flights we take
C. mitigate the force of her argunent by suggesting that there is an alternative approach
D. suggest an alternative that will reduce the effect of pollution
