During 2012, Joule Company, a sole proprietorship, earned general business tax credits of $30,000 for energy conservation and rehabilitation expenditures. The owner, Mark Joule, knows that the overall credit will belimited. He provides you with the following information for 2012: regular tax (before credits) $37,500; tentative minimum tax $20,200; alternative minimum tax $0; foreign tax credit $4,500; other nonrefundable credits $6,100. Mark also has a $3,000 carryforward of general business credit from 2011.

a. What is the 2012 limitation on Mark's general business credit?
b. What is Mark's allowable general business credit in 2012 and where does it come from?
c. What is Mark's general business credit carryover?