The Trustee of the Dan Durrell Trust Is Authorized to Pay

The trustee of the Dan Durrell trust is authorized to pay to the wife $10,000 per year and at, his or her discretion, distribute income or corpus to the beneficiary. In 2012, the trustee has DNI of $20,000; the trustee distributes $10,000 to the wife as required and $25,000 at the trustee's discretion. How much is the wife taxed on?

A) $20,000
B) $35,000
C) $15,000
D) $10,000