On January $1,2023,$ George Brown College purchased equipment for $$60,000.$ It was expected to last $5$ years, after which it will be sold for $$5,000.$ It is expected to be used for a total of $10,000$ machine hours, and was used for $750$ hours during the year ended December $31,2023.$

$($a$)$ Please calculate the depreciation expense for the end of $2023$ using the straight$-$line method.

$($b$)$ Please calculate the depreciation expense for the end of $2023$ using the units$-$of$-$production method.

$($c$)$ Please calculate the depreciation expense for the end of $2023$ using the double diminishing$-$balance method.