Answer:
170,000
Explanation:
With $600,000 of book income, the potential total book tax expense is $210,000 ($600,000 × 35%). However, the release of the $40,000 valuation allowance in the current year allows an additional $40,000 of future tax benefits (savings) to be considered in the current year. Accordingly, the total tax expense is $170,000 ($210,000 – $40,000).