Everybody at a company is assigned a unique $9$ digit ID$.$

A$)$ How many unique IDs exist? $($NOTE: You should also count the ID consisting of all zeros$)$

$1000000000$

B$)$ If only IDs divisible by $2$ are allowed, h

C$)$ If only IDs divisible by $5$ are allowed, how many unique IDS exist?

D$)$ If only IDs divisible by $5$ and $2$ are allowed, how many unique IDs exist?

E$)$ If only IDs divisible by $5$ or $2$ are allowed, how many unique IDs exist?