A machine that costs Php$10,000$ was sold as scrap value after being used for $10$ years. If the scrap value was Php$500,$ determine the depreciation charge and the book value during the $4$th year using a$)$ SLM; b$)$ DBM; c$)$ DDBM; d$)$ SYDM; e$)$ SFM $($i$=6\%)$