A Diels-Alder reaction of 2,5-dimethyl furan and maleic anhydride gives compound A that undergoes acid-catalyzed dehydration to form 3,6-dimethylphthalic anhydride. What is the product formed in the acid-catalyzed dehydration of compound A?
1) 3,6-dimethylphthalic anhydride
2) 2,5-dimethyl furan
3) maleic anhydride
4) compound A