Q$-1-$From the given information, calculate the cost of inventory as well as the cost of goods sold using the $($a$)$ specific invoice, $($b$)$ weighted$-$average, $($c$)$ first$-$in$,$ first$-$out, and $($d$)$ last$-$in$,$ first$-$out methods.

$\backslash$table$[[$Date$,$Units,Cost per unit,Total Cost$],[$March $1,50,15,750],[$June $5,30,16,480],[$September $4,40,17,680],[$November $3,30,18,540]]$

Additional Information:

$20$ Units from March $1$

$10$ Units from September $4$

$5$ Units from November $3$

Also, mention which method organization should follow to reduce taxes?