$1.$ Actuary and trustee reports indicate the following changes in the PBO and plan assets of Spartan Inc. during $2024$: Prior service cost at Jan. $1,2024,$ from plan amendment at the beginning of $2021($amortization: $\backslash (\backslash$$ $4\backslash )$ million per year$)$ Net Gain$-$AOCI at Jan. $1,2024($previous losses exceeded previous gains$)$ Average remaining service life of the active employee group Actuary's discount rate $\backslash$$$28$ million $\backslash (\backslash$$ $80\backslash )$ million $10$ years $8\backslash \%(\backslash$$ in millions$)$ PBO Required: Determine the company's pension expense for $2024.(7$ points$)$