The notes to financial statements present information on significant accounting policies, complex or special transactions, details of reported amounts, commitments, contingencies, segments, quarterly data, and subsequent events. Indicate which type of note disclosure is illustrated by each of the following notes:

a. The company has agreed to purchase seven EMB-120 aircraft and related spare parts. The aggregate cost of these aircraft is approximately \(\$ 52,000,150\), subject to a cost escalation provision. The aircraft are scheduled to be delivered over the next two fiscal years.

b. The company has deferred certain costs related to major accounting and information systems enhancements that are anticipated to benefit future years. Upon completion, the related cost is amortized over a period not exceeding five years.

c. The company has guaranteed loans and leases of independent distributors approximating \(\$ 27,500,000\) as of December 31 of the current year.

d. An officer of the company is also a director of a major raw material supplier of the company. The amount of raw material purchases from this supplier approximated \(\$ 595,000\) in the current year.