Choice "C" is correct. When a discount on a bond or note is amortized, the discount amortization increases interest expense for the period.
Choice "b" is incorrect. Pension plan interest is reported as a component of net periodic pension cost.
Choice "a" is incorrect. Deferred compensation plan interest is reported as a component of deferred compensation plan expense.
Choice "d" is incorrect. Interest incurred to finance software developed for internal use is capitalized as a component of computer software development costs.