Application of tax.

The tax imposed by Chapter 103, Subchapter A (relating to persons subject to tax) is to be paid by the beneficiary of an estate or trust if the income upon which the tax is based is received by the estate or trust and, under the governing instrument and applicable State law, is required to be distributed to the beneficiary currently or is in fact paid or credited to him. The tax imposed by Chapter 103, Subchapter A is to be paid by the estate or trusts only if the income upon which the tax is based is not required to be distributed to the beneficiary currently and is not in fact paid or credited to him.