Given the MongoDB query below, what will it do$?$

db$.$orders.aggregate$([$

$\{$$match: status: "delivered" $\}\},$

$\{$$group: $\{\_$id: $"$$customer$\_$id$",$ total: $\{$$sum: $"$$amount" $\}\}\}$

$])$;

Inserts a new order with status "delivered"

Deletes all delivered orders

Retrieves total amount for each customer with delivered orders

Retrieves total amount for each delivered order