When calculating return on net operating assets, interest expense net of tax is added back to net income for purposes of calculating the numerator. What tax rate should be used?

Below is selected information from Tricrop.

Year $1$ Year $2$

Net operating assets$/$common equity $1\mathrm{.}371\mathrm{.}53$

Net operating profit margin $19\%21\%$

Income tax rate $47\%28\%$

Revenues$/$average net operating assets $0\mathrm{.}810\mathrm{.}61$

EBIT$/$revenues $38\%32\%$

Question $5$ options:

Estate tax rate

Marginal tax rate

Statutory federal tax rate

Statutory federal tax rate plus statutory state tax rate