iv$.$ Consider a forward contract on gold. Suppose that there is fixed storage cost of $c per ounce, paid at the end period and c is the same for any time period less than one year. Let St be the spot price of one ounce of gold at time t and r be the continuously compounded risk$-$free rate of interest which is assumed to be constant. Derive the price at time t of a forward contract written one ounce of gold at the start of the start of the year, with maturity T year $($T$<1)$