Parent and Subsidiary Corporations Form an Affiliated Group How Much of Subsidiary's Loss Can Be Carried Back to Year

Parent and Subsidiary Corporations form an affiliated group.Last year,the initial year of operation,Parent and Subsidiary filed separate returns.This year,the group files a consolidated tax return.The results for last year and the current year are: $$\begin{array}{l}\text { Taxable Income }\\\begin{array} { l | r | r } \hline & { \text { Last } } & { \text { Current } } \\\hline \text { Parent } & ( \$ 10,000 ) & \$ 50,000 \\\hline \text { Subsidiary } & 30,000 & ( 25,000 ) \\\hline\end{array}\end{array}$$ How much of Subsidiary's loss can be carried back to last year?

A) $0
B) $20,000
C) $25,000
D) none of the above