Write the following SQL inquiry $($found below this$),$ based of the database schema:

Product$($maker$,$ model, type$)($c$)$ Sample data for relation Printer

PC$($model$,$ speed, ram, hd$,$ price$)$

Laptop$($model$,$ speed, ram, hd$,$ screen, price$)$

Printer$($model$,$ color, type, price$)$

$-$ Find the average price of PCs made by manufacturer $"$A$."-$