M10-27. Analyzing Footnote Disclosure of Pension Income In its 2018 10-K. Norfolk Southern Railroad reported the following in a footnote labeled "Other income, net." ($ in millions) 2018 2017 2016 Net pension and other postretirement benefit cost. . . ... $61 $ 64 $ 65 Rental income. .... .. . . . Ill 5 87 93 External advisor costs (20) Othe... . . . . 1 81 5 (2) Total . . . . $67 $156 $136 Required a. Explain how Norfolk Southern could report "income" of $61 million related to its pension and other postretirement plans as opposed to an expense. b. For purposes of analysis, would we classify this "Other income, net" as operating or nonoperating