In general

The amount allowed as a deduction under this chapter for any taxable year for business interest shall not exceed the sum of—

(A) the business interest income of such taxpayer for such taxable year,

(B) 30 percent of the adjusted taxable income of such taxpayer for such taxable year, plus

(C) the floor plan financing interest of such taxpayer for such taxable year.

The amount determined under subparagraph (B) shall not be less than zero.