A taxpayer takes out $150,000 of a loan against their property as a home equity line of credit, using most of the funds for personal uses. In the end, about $15,000 of the loan is used to renovate part of their main home. They paid $5,000 in interest during the year. How much of this interest can be treated as mortgage interest for the purposes of itemized deductions? (Not how much are they using on a Schedule A; We don't have enough information for that. How much is POTENTIALLY deductible with the given information?)