$1.$ A set of office equipment costs $$100,000$ and has a useful life of $6$ years. Its estimated market value at the end of the $6$th year is $$5,000.$ Determine the depreciation amount on the $4$th year and the book value at the end of the $3$rd year using:

a$.$ Straight Line Method

b$.$ Double Declining Balance Method

c$.$ Sum$-$of$-$Years Digits Method

d$.$ Declining Balance Method with Switchover to SL

e$.$ MACRS GDS $($assume that the assets will be disposed of on the $3$rd year$)$

f$.$ MACRS ADS