Ringgold Company Experienced an Event That Affected Its Financial Statements

Ringgold Company experienced an event that affected its financial statements as indicated below: $\begin{array}{|c|c|c|c|c|c|c|c|c|c|c|c|}\hline & \text { Assets }&&= & \text { Liab. } & + & \text { Equity } & \text { Rev. } & - & \text { Exp. } & = & \text { Net Inc. } \\\hline \text { Mfg. } & + & \text { WIP } & & & & & & & & \\\text { OH }& &\text { Inv. }\\\hline (1,200) & + & (1,200) &= & \mathrm{n} / \mathbf{a} & +&\mathrm{n} / \mathrm{a} & \mathrm{n} / \mathrm{a} & -&\mathrm{n} / \mathrm{a} & = & \mathrm{n} / \mathrm{a} \\\hline\end{array}$ Which of the following accounting events caused the indicated effects on the company's accounting equation?

A) Actual overhead cost was incurred
B) Underapplied overhead was written off
C) Estimated overhead was charged to production
D) None of these.