Final answer:
In Becki's case, only the $4,300 of the alternative minimum tax attributable to long-term construction contract differences may potentially be eligible to be carried forward as a credit against future regular tax liabilities, since this portion is considered a deferral item.
Step-by-step explanation:
The student has asked how much of the alternative minimum tax (AMT) Becki paid during Year 3 can be used as a credit against her future regular tax. To address this, we must acknowledge that only certain parts of the AMT can be carried forward as credits in future years.
Specifically, the portion of the AMT that is attributed to deferral items, such as incentive stock options or depreciation differences, can be carried forward. Conversely, AMT attributable to exclusion items such as standard or itemized deduction add-backs is not eligible to be carried forward as a credit. In Becki's case, it is stated that $8,100 of her AMT was due to itemized deduction add-backs and the remaining $4,300 was due to long-term construction contract differences.
Because the long-term construction contract differences are considered deferral items, this part of the AMT could potentially be eligible to be used as a credit in future years. However, the $8,100 related to itemized deduction add-backs would not qualify since they are exclusion items. Therefore, Becki may be able to carry forward a credit of $4,300 against future regular tax liabilities.
It is important to note that AMT credits are governed by specific tax laws, which can change, and therefore taxpayers should refer to the most current IRS regulations or consult with a tax professional to determine eligibility and the accurate calculation of such credits. Without current, specific tax law details provided in the question, we can only present a general explanation based on typical AMT credit rules.