The required production of Libra Manufacturers for October $2024$ is $10000$ units Product A$.$ Each unit requires two kilograms of materials. The manufacturer desires inventory of $2000$ kilograms of materials on $31$ October $2024$ but expects to have inventory of $1400$ kilograms on $01$ October $2024.$ How many kilograms of mater should be purchased?

A$.20600$

B$.19400$

C$.10600$

D$.20000$